fix: September 16 core audit — partial saves, asset path safety, auto-update, display settings the library refuses, scroll speed (#595)

* fix(sports): share the ESPN rejected-range memo with the background service

BackgroundDataService always sent a season range first and, on a 400,
fell back to chunks without recording the rejection, so every background
season fetch spent a doomed request and live scoreboards learned nothing
from it (or it from them). The worker now consults and sets the same
6-hour memo fetch_espn_scoreboard() uses: a known rejection goes straight
to month/day chunks, and if every chunk fails the range is asked once for
a real error without re-spending the chunks.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): keep plugin asset and action routes inside their directories

POST /plugins/assets/upload, GET /plugins/assets/list and POST
/plugins/assets/delete joined the request's plugin_id onto assets/plugins
unchecked, so '../../config' created, wrote, listed and deleted outside
it. #561 guarded only the route that serves the files. All three now go
through path_safety.resolve_under and answer 400 for anything but a
plain name, and delete only unlinks a metadata path that resolves into
that plugin's uploads directory.

PluginManager.get_plugin_directory refuses ids that are not one plain
path segment, so /plugins/action (which runs a manifest script from the
returned directory) and every other caller get the guard; the action
route also rejects such ids up front, covering its no-manager fallback.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): report a no-op plugin update as already up to date

update_plugin() returns True both for a real update and for "nothing to
do" (a ZIP-installed monorepo plugin already at the registry version, a
bundled plugin). With no git commit to compare, POST /plugins/update
called every such success "updated successfully", so Check & Update All
counted most official plugins as updated on every run.

The route now reads what changed off the plugin itself (commit, else
manifest version, else last_updated) and returns data.update_status
(updated / up_to_date / local_only). The update-all toast is summarised
by PluginInstallManager.summarizeUpdateResults from that status, falling
back to the message for older servers.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(sports): scoreboard scroll speed no longer follows target_fps

sports_scroll computed the crisp speed ladder against the global
target_fps whenever limit_refresh_rate_hz was the 100 Hz default. Since
frame-locked presentation (#545) the helper steps a fixed number of whole
pixels per presented frame and the panel presents at its real refresh, so
the General tab's "Scroll Frame Rate" became a speed multiplier: 60 ran a
50 px/s scoreboard at 100 px/s, 200 ran it at 25 px/s.

The ladder now uses the display manager's refresh_hz, then
display.hardware.limit_refresh_rate_hz, then the default. target_fps is
not consulted. Docstrings now say scroll_delay is ignored for pacing (no
behaviour change there) and describe the fixed-step model.

Tests: replace the tests that pinned target_fps as the ladder refresh and
described time-based stepping; assert speed independence from target_fps
(unit and end-to-end presented px/s against the real helper), that the
fixed per-frame step is applied, and that scroll_delay does not change
speed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): escape registry and upload values in plugin manager inline handlers

The store, saved-repository and custom-registry buttons built
onclick='...(${JSON.stringify(id)})...'. JSON.stringify leaves ' alone,
so a custom registry entry whose id contained ' closed the attribute and
added its own handler. One helper, jsStringAttr(), now HTML-escapes the
JSON literal for every one of those handlers, and the store View button
opens only http(s) repo links.

The live window.updateImageList (plugins_manager.js loads last, so its
copy wins over the file-upload widget's) wrote the uploaded file's
original name, path and ids into markup raw; they are escaped now.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(changelog): note plugin asset, action and inline handler guards

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(update): let the root pip wrapper install web_interface/requirements.txt

Update Code, the automatic update's health check and Install Base
Requirements install web_interface/requirements.txt through
safe_pip_install.sh, which only allowed the root requirements.txt. The
first commit changing that file would fail its dependency install, and
the automatic updater rolls back any update whose dependencies did not
install -- on every device, for every newer commit.

The wrapper now lists both core requirement files. Only their folders
are resolved, so a requirements.txt symlinked out of the project is
compared by its target and refused (previously the root file's own
symlink target was what got allowed). The updater's file list is a
named constant, and a test runs the real wrapper (pip stubbed) on
every file Update Code and the rollback install.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): do not retry plugin requests that got an HTTP answer

PluginAPI.request wrapped everything that was not a structured error as
NETWORK_ERROR: a proxy's 502 HTML page (response.json() throws) and a
JSON error without error_code included. Check & Update All retries
NETWORK_ERROR, so those updates were re-sent five more times with
backoff, contrary to the #587 contract that an HTTP error response is
the server's answer.

NETWORK_ERROR now means only that fetch() rejected. Any HTTP response
without an error_code, or with a body that is not JSON, is API_ERROR
with the HTTP status attached. Tested against the shipped api_client.js.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(scroll): restart the stats window when an idle gap is dropped by size

#582 dropped an idle gap from the frame stats two ways: the reset_scroll()
sentinel, which also restarts the 5s window timer, and a size guard for
scrollers that never call reset_scroll(), which did not. On that path the
first real frame after the gap found the boundary overdue and logged a
stats line for a one-frame window. Both paths now share one seeding helper.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(update): leave plugins alone when update_core's own rollback fails

update_core returns rollback_failed directly when a partial pull or an
update whose health check never started cannot be rolled back. run()
only held plugins back for 'verifying', so those devices still got new
plugin versions and a display restart on top of a core in an unknown
state -- the opposite of what the health-check path does, and of the
3.4.0 changelog (plugins are left alone if the rollback fails).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(api): make the REST reference match the api_v3 package

Every documented request body, query parameter and response shape was
re-checked against the handlers in web_interface/blueprints/api_v3/.
Fixes calls that failed as documented (repo_url, action_id/params,
files/image_id, font_file+font_family, ?font=, cache key,
auto_enable_ap_mode, plugin limit keys), removes the font-override
endpoints dropped in #566, corrects response shapes (plugins/config,
plugins/schema, health, metrics, operation history, github-status,
fonts/catalog, cache/list, logs, wifi, on-demand, SSE streams), and adds
the 26 routes it omitted (backup, system auto-update/git, wifi radio,
starlark editor, MQTT bridge, status endpoints, skins).

Documents the merge semantics of partial JSON saves to /config/main and
/plugins/config and the dim-schedule POST accepting GET's days shape,
which land in the same change set. Replaces app.py line numbers and the
removed api_v3.py path with file and function names.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): remove the General-tab plugin system toggles that did nothing

plugin_system.auto_discover, auto_load_enabled and development_mode had
General-tab toggles whose help tips promised dormant plugins and verbose
logging, but nothing reads them: every enabled plugin is discovered and
loaded regardless. Remove the three toggles.

The keys stay tolerated in stored configs. The save handler now stores
a flag only when a client sends it; treating a missing key as an
unchecked box would otherwise rewrite all three to false on every
General-tab save, which still posts plugins_directory.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* refactor(scroll): remove dead code left by #523/#570

- Drop the optional scipy.ndimage import and HAS_SCIPY; nothing read
  them since the numpy blend replaced the scipy path.
- Drop ScrollHelper._last_integer_position and frame_time_target, which
  were written but never read.
- Keep target_fps and set_target_fps() but document them as
  informational: nothing paces off them, yet ledmatrix-elections'
  test_scroll_pacing.py reads helper.target_fps back and third-party
  plugins may call the setter.
- Fix stale comments: fixed_pixels_per_frame's "use scroll_delay to
  throttle", set_sub_pixel_scrolling's "default: True", and
  set_frame_based_scrolling's claim that it steps.

The plugins monorepo was grepped for every removed name; none is used.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(fonts): point plugins at plugin_manager.font_manager; drop removed overrides UI

FONT_MANAGER.md told plugins to read display_manager.font_manager, which
does not exist, so a plugin following it failed to load with
AttributeError. The shared FontManager lives on the PluginManager and
BasePlugin._get_font_manager() returns it (with a fallback for harnesses).

Also removes the Fonts-tab override workflow and element-override panels
that #566 deleted, from FONT_MANAGER.md and WEB_INTERFACE_GUIDE.md.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(store): search via /plugins/store/list?query=; send Content-Type on registry curls

/plugins/store/search does not exist (404) and the list endpoint reads
query, not q. The registry guide's curl examples omitted the JSON
Content-Type, so the handlers saw an empty body and answered 400.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(config): use the shared core-key list in the last three private copies

StartupValidator warned "Plugin 'auto_update' is enabled but not found" on
every display start with auto-update or a dim schedule on; the reserved
plugin-id check missed auto_update, sync, location and the rest; and
ConfigManager's (uncalled) orphan cleanup would have deleted display,
schedule and auto_update. All three now read src/core_config_keys.py, which
also gains CORE_SECRETS_KEYS for the github/youtube secrets sections.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): partial JSON saves to /config/main change only what they send

A JSON body with one field reset every checkbox in the sections it touched:
the MQTT bridge's brightness slider turned off disable_hardware_pulsing,
inverse_colors, show_refresh_rate and use_short_date_format, and a
timezone-only save turned off web-UI autostart and weekly auto-updates.
Missing-means-unchecked now applies only to form posts: form-encoded bodies
and the v3 forms, which mark themselves with a hidden __form_section input.

Also on the config routes:
- vegas_min/max_cycle_duration no longer match the generic *_duration rule,
  so they stop landing in display_durations and a blank one no longer
  rejects the whole Display save;
- saving from the Raw JSON editor calls start_setup_if_needed like the
  General form, so enabling auto-update there finishes its setup;
- the schedule and dim-schedule POSTs accept the per-day days.<day> shape
  their GETs return, as well as the flat form keys.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(scripts): install plugin dependencies from the configured plugins directory

install_plugin_dependencies.sh scanned only plugins/, but the Plugin
Store installs into plugin_system.plugins_directory (default
plugin-repos), so the documented "Recommended" fix found 0 plugins on
every store install. It now reads plugins_directory from
config/config.json (relative to the project root or absolute, default
plugin-repos) and also scans plugins/ for dev symlinks, installing a
plugin reached through both only once.

With set -e alone, `pip ... | tee` took tee's exit status, so a failed
pip install was reported as success; set -o pipefail.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs: replace stale API names, line numbers and the api_v3.py path

- ADVANCED_FEATURES: StreamManager methods that exist
  (get_next_segment, take_next_group, refresh, advance_cycle, ...), and the
  real on-demand status envelope ({status, data: {state, service}})
- app.py:199 / :144 / :607-619 line citations and
  web_interface/blueprints/api_v3.py (now a package) replaced with file and
  function names in ADVANCED_FEATURES, CONFIG_DEBUGGING,
  PLUGIN_ARCHITECTURE_SPEC, PLUGIN_QUICK_REFERENCE,
  PLUGIN_CONFIGURATION_TABS, TROUBLESHOOTING and web_interface/README
- CONFIG_DEBUGGING: partial /config/main saves change only sent keys; use
  /config/raw/main to replace the file; describe where validation runs
- TROUBLESHOOTING: clear_cache.py needs --clear-all (no args only prints
  usage)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(scripts): verify the web interface that actually ships, on port 5000

verify_installation.sh failed every healthy install: it required the
long-removed web_interface_v2.py and looked for a listener on port 5001,
while the web interface binds 5000 (web_interface/start.py). It now
checks the files ledmatrix-web.service runs (start_web_conditionally.py,
web_interface/start.py, app.py) and port 5000. verify_web_ui.sh had the
same 5001 port in its listen check, HTTP probe and printed URLs.

Port matches are anchored so :50001 no longer counts as :5000.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(plugins): one display-size contract: display_manager.width/height

CLAUDE.md (#580) says to read display_manager.width/height because
matrix is None when hardware init fails; the development guide, the
safety-harness doc and two DisplayManager docstrings still recommended
matrix.width/height. The bundled starlark-apps plugin read matrix.width
unguarded, so its magnify recommendation and frame scaling raised in
fallback mode (e.g. after the Pi 5 hardware refusal).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(install): make install_service.sh --help print usage instead of installing

install_service.sh parsed no arguments, so `sudo ./scripts/install/
install_service.sh --help` (presented as harmless in MIGRATION_GUIDE.md)
rewrote ledmatrix.service, ledmatrix-web.service and both update-verify
units and enabled/started them. It now handles -h/--help (usage, exit 0,
no changes) and rejects any other argument with exit 2 before doing
anything. Running it with no arguments, as first_time_install.sh does,
is unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(scroll): describe the fixed-step model and document frame_hold

Since #545 a crisp speed from scroll_config.configure() makes the helper
advance a fixed whole-pixel step per presented frame with no clock, and the
display manager's frame hold is part of the speed. The docs still described
the removed wall-clock model:

- scroll_config's module and configure() docstrings said speed is applied
  in time-based mode and that omitting the hold "falls back to fractional
  pixels"; omitting it actually runs the scroll frame_hold times too fast.
- SCROLL_PERFORMANCE.md said ScrollHelper accumulates elapsed time in both
  modes, and read a 20 ms stats median as missed refreshes although that
  is a healthy 50 px/s (hold 2) scroll. It now explains the fixed step,
  the hold-dependent healthy median, that target_fps plays no part, and
  that a hand-added scroll_pixels_per_second loses to a schema-default pair.
- PLUGIN_API_REFERENCE.md documented set_scrolling_state(is_scrolling)
  without frame_hold; it now documents the parameter (core 3.4.0) with a
  configure() + set_scrolling_state example.
- update_scroll_position/set_scroll_speed and set_scrolling_state
  docstrings say the same.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(config): mark target_fps legacy; describe what Vegas scroll_delay does

- General tab "Scroll Frame Rate" (target_fps) is labelled legacy: after
  the sports_scroll fix nothing in core scrolling reads it. The field and
  its API validation stay so saved configs and plugins that read
  global_config['target_fps'] keep working. CONFIG_REFERENCE says the same.
- Vegas frame_based_scrolling/scroll_delay were described as frame-count
  stepping at ~50 FPS. Neither steps nor sets a frame rate: frame-based
  mode converts the speed to px per scroll_delay, clamps it to 0.1-5, and
  still advances by elapsed time, so the applied speed is
  clamp(scroll_speed * scroll_delay, 0.1, 5) / scroll_delay px/s. The
  config comments, render_pipeline comment and CONFIG_REFERENCE rows now
  say so. No behaviour change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(deps): describe how plugin dependencies are really installed

The guides said the web service runs as root, that installs pick --user
from os.geteuid(), and quoted a warning and a
PluginManager._install_plugin_dependencies() method that don't exist. The
web unit runs as the installing user; store installs go through
install_requirements_file() and sudo safe_pip_install.sh (root), with a
user-level fallback that says so, and load-time installs run in the
display service's own (root) interpreter.

Manual paths now use the configured plugins directory (plugin-repos/ by
default) instead of plugins/, which store installs no longer use, and
install_plugin_dependencies.sh is described as scanning that directory.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(update): count local changes one way for the preflight and the pull

The automatic update's preflight ignored mode-only changes and anything
whose status line contained plugins/ or plugin-repos/, then promised
"Automatic updates will not stash your changes". perform_core_update
used plain git status (modes count) and ignored only 'plugins/', then
ran 'git stash push -- :!plugins', which nothing ever pops. So an edit
to a bundled plugin under plugin-repos/, or the installer's chmods on
tracked scripts, passed the preflight and was stashed away for good.

- auto_update.local_changes() is the one predicate both use:
  core.fileMode=false, porcelain -z, and plugins/ and plugin-repos/
  excluded by leading folder rather than substring (a core file under
  web_interface/static/v3/js/plugins/ now counts).
- Update Code's explicit stash leaves out both plugin folders; the
  pull's --autostash carries their edits and mode changes across and
  reapplies them.
- The automatic updater calls perform_core_update(stash_local_changes=
  False), which refuses instead of stashing edits that appeared after
  the preflight; update_core reports that as 'blocked'.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(scripts): diagnostics follow the web autostart default and api_v3 package

#556 made a missing web_display_autostart mean "start" (only an explicit
false/off keeps the web interface down), but the diagnostics still said
otherwise: diagnose_web_ui.sh reported a missing key as "defaults to
false", diagnose_web_interface.sh said the web interface "will not start
unless this is set to true" and recommended enabling it, and
debug_web_manual.py printed False. Troubleshooting a down web UI pointed
users at a non-cause.

Both shell scripts now evaluate the setting with the launcher's own
autostart_enabled() (inline fallback if it cannot be imported) and report
on / off / not set (on) / unparseable config; debug_web_manual.py uses
the same function. They also check web_interface/blueprints/api_v3/
__init__.py: api_v3.py became a package in #553, so every healthy
checkout was reported as missing a file.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(install): what install_service.sh installs; verify script port; no sudo for --help

install_service.sh installs and starts ledmatrix, ledmatrix-web and the
update-verify units, not only ledmatrix.service (systemd/README.md,
README.md). MIGRATION_GUIDE presented 'sudo install_service.sh --help'
as a harmless check; it now shows --help without sudo and warns what a
real run does. SSH_UNAVAILABLE_AFTER_INSTALL: verify_installation.sh
checks the web interface on port 5000.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(changelog): note update-all, plugin system settings and script fixes

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(display): size the preview after orientation and pixel mappers

display_geometry.physical_size claimed to give DisplayManager's answer but
only computed cols*chain x rows*parallel. RGBMatrix.width/height are measured
after the library's pixel mappers, so a Rotate:90 / orientation 90 chain
previewed 128x32 for a 32x128 panel and a U-mapper chain of four 256x32 for
128x64.

Model the built-in mappers' size effect as the pinned lib/pixel-mapper.cc
does (Rotate, U-mapper, V-mapper, StackToRow, Remap; Mirror and unknown
names leave it alone), and move the orientation composition here so
DisplayManager and the preview share it. The module docstring no longer
claims the sync handshake uses it; that imports only DEFAULT_CHAIN_LENGTH.

Audit finding F18.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(display): refuse settings the rgbmatrix library aborts on, on every board

The library answers several settings with a NULL matrix or abort() rather
than an error, so the display service crash-looped (Restart=on-failure)
instead of reaching fallback mode: rows above 64, chain_length above 255
(uint8_t binding setter, documented as "no upper limit"), a misspelled
hardware_mapping, and parallel 2-3 on a single-output mapping, reachable
from the Display form on the default adafruit-hat(-pwm) mapping. #586 only
guarded the Pi 5 subset.

- src/matrix_support.py holds the rules for every board (Options::Validate
  ranges, binding integer types, mapping names and outputs from
  lib/hardware-mapping.c) plus the Pi 5 ones, and is the one source of the
  API's numeric ranges.
- DisplayManager checks them before building options and raises
  MatrixSettingsRefused, so a hand-edited config falls back with a logged,
  reported reason. Emulator mode only warns.
- The config API refuses them with a 400 naming the setting; combinations
  are checked against stored values but reported only when the request
  sets a field involved.
- The hardware status file gains "cause" (settings/library/forced). The
  fallback log and Display banner give the Pi 5 rebuild hint only for a
  library failure instead of rebuild + gpio_slowdown advice for every
  failure; one Pi 5 slowdown recommendation (1-3, start at 1).
- The Display form offers classic/classic-pi1 and orientation 90/270 and
  renders any other stored mapping selected with a warning, so an
  unrelated save no longer rewrites them; the API accepts 90/270.

Audit findings F03, F16, F19, F21.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(display): library limits, template defaults and Pi 5 slowdown

- rows 8-64, chain_length 1-255, parallel limited by the mapping's outputs,
  classic/classic-pi1 mappings and orientation 90/270 documented.
- Defaults are the config.template.json values: config migration adds
  missing keys from the template, so the listed "code defaults" never
  applied.
- One Raspberry Pi 5 gpio_slowdown recommendation: 1-3 in PIO mode,
  starting at 1.
- Troubleshooting describes the refused-settings fallback, and CHANGELOG
  corrects the Unreleased "no upper limit" entry.

Audit findings F19, F20, F21.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(scripts): scroll_speeds.py opens the panel with the service's options

--measure and --demo built RGBMatrixOptions from a private copy of the
display service's builder that had drifted: gpio_slowdown came from
display.hardware (default 2) instead of display.runtime (default 3), and
rp1_rio, panel_type, disable_hardware_pulsing, inverse_colors,
pixel_mapper_config and orientation were skipped, with different defaults
(hardware_mapping "regular", pwm_bits 11). A panel needing a high slowdown
was measured -- or garbled -- in a setup the service never drives.

The option filling in DisplayManager._setup_matrix moves, unchanged, into
DisplayManager.apply_matrix_options(options, config), which _setup_matrix
calls and the script reuses (overriding only limit_refresh_rate_hz for
--measure). The script now loads the whole config rather than the hardware
block. Tests pin the script's options to the service's attribute for
attribute.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(scripts): scroll_speeds.py recommends keys the resolver honours

The ladder ended by telling users to set
display_options.scroll_pixels_per_second. scroll_config ranks that key
below the scroll_speed + scroll_delay pair, deliberately, and several
plugin schemas default the pair into config, so the advised key was
silently ignored (a schema-default 1/0.02 pair plus an advised 66 still
resolved to 50 px/s).

The advice is now the pair that selects the crisp speed exactly
(pixels_per_frame every frame_hold/refresh seconds), explains that the
pair outranks scroll_pixels_per_second, and gives the scoreboards'
per-league scroll_settings.scroll_speed (px/s) form. Tests resolve the
printed pair over a schema-default pair and check it lands on the
advertised speed and hold.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs: withdraw the target_fps claim for sports_scroll; fix the Vegas speed formula

- SPORTS_UNIFICATION.md still presented honouring global target_fps as
  sports_scroll's added behaviour and its one user-visible gain; note that
  it was withdrawn because it had become a speed multiplier.
- ADVANCED_FEATURES.md gave Vegas scrolling as
  (scroll_speed / target_fps) * elapsed; the real rule is scroll_speed px/s
  by elapsed time, through a 0.1-5 px per scroll_delay clamp when
  frame_based_scrolling is on.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(changelog): scroll model fixes

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(dev): link-github links plugins from the ledmatrix-plugins monorepo

link-github <name> cloned https://github.com/ChuckBuilds/ledmatrix-<name>.git,
and those per-plugin repositories no longer exist: official plugins are
directories in the ledmatrix-plugins monorepo. It now clones (or pulls) the
monorepo once into the dev directory, finds plugins/<name>,
plugins/ledmatrix-<name> or the plugin whose manifest id is <name>, and
links it under its manifest id. With an explicit repo URL it still links a
single-repository plugin as before.

dev_plugins.json: github_user is honoured again (monorepo owner, e.g. a
fork), plus plugins_repo and plugins_branch; github_pattern, which was
documented but never read, is dropped and warned about. Ships
dev_plugins.json.example and git-ignores dev_plugins.json, both of which
the guide promised. Reading JSON falls back to python3 when jq is missing
(get_plugin_id silently returned nothing without jq).

update/status/list find the git checkout above a monorepo plugin
directory (its .git is not in the plugin dir), and update pulls a shared
checkout once. status no longer exits 1 when nothing is broken.

Docs: PLUGIN_DEVELOPMENT_GUIDE (quick start, link-github, configuration,
workflow, store integration, hello-world link, submission), and the
nonexistent scripts/git-hooks/pre-push-plugin-version and
scripts/bump_plugin_version.py replaced with the real rule: bump the
manifest version and run update_registry.py. scripts/dev/README.md and
CLAUDE.md updated to match.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(scripts): monorepo workspace layout; fix_perms and install READMEs

MULTI_ROOT_WORKSPACE_SETUP described one sibling repository per plugin;
setup_plugin_repos.py links ../ledmatrix-plugins/plugins/* into
plugin-repos/ and update_plugin_repos.py pulls only the monorepo, and the
workspace file opens LEDMatrix plus ../ledmatrix-plugins.

scripts/fix_perms/README.md listed cache directories
fix_cache_permissions.sh never touches and a 'ledmatrix' service user
that doesn't exist (also in scripts/install/README.md); adds
safe_pip_install.sh. install/README: install_service.sh installs the web
and update-verify units too.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(update): keep the rollback's pip retries inside the unit time limit

The health check reinstalled the previous requirements by trying the
next bash path after any failure, including a 600 s pip timeout. Two
files, two paths: up to 40 minutes of pip alone, while systemd stops
ledmatrix-update-verify.service at TimeoutStartSec=30min -- killing the
rollback half-way and leaving the update 'verifying' until the web UI
calls it lost.

- Like permission_utils.install_requirements_file, only a sudo refusal
  moves on to the next bash; a pip that ran and failed or timed out is
  not repeated. The refusal wording is one list
  (permission_utils.SUDO_REFUSAL_PHRASES), mirrored in the stdlib-only
  verifier and pinned equal by a test.
- All reinstalls in one rollback share a 600 s budget.
- WORST_CASE_SECONDS adds up every timeout on the longest path (27.5
  min); a test holds it under the unit's TimeoutStartSec and that under
  the web UI's VERIFY_LOST_SECONDS.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(plugins): prepare plugin configs one way for load, saves, GET, hot reload and dev tools

Plugin config was prepared differently depending on how it arrived:

- JSON POST /plugins/config built a partial body on schema defaults, so
  {"enabled": true} reset every other setting of the plugin. It now merges
  onto the stored section first, as the form path already did.
- Legacy-boolean normalization (#588) ran only at load: GET /plugins/config
  returned the raw boolean, posting it back failed validation, and hot
  reload handed plugins the raw section (a legacy dynamic_duration: true
  came back as a boolean). schema_manager.prepare_plugin_config (normalize,
  then defaults) is now used by PluginManager.load_plugin, both save paths,
  GET, the save notifications and DisplayController's hot-reload callback.
- The JSON save's filter kept only enabled/display_duration/live_priority
  and dropped a submitted skin, skin_options or vegas_* tuning key. There
  is now one core-owned per-plugin list, schema_manager.CORE_PLUGIN_PROPERTIES,
  used by validation and by the save filter; PluginManager's
  CORE_OWNED_CONFIG_KEYS is its vegas subset.
- Plugin sections posted to /config/main were stored verbatim, including
  values /plugins/config rejects. They now go through the same preparation
  (_prepare_plugin_config_for_save, extracted from save_plugin_config), and
  a failing section rejects the whole save before anything is written.
- dev_server read only top-level defaults and let a schema enabled:false
  win; build_full_config shallow-merged overrides, dropping sibling
  defaults; the harness extracted defaults differently from the device.
  loading.build_config now uses the device's extraction and preparation,
  and dev_server, check_plugin, render_plugin and the harness all use it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(mqtt-bridge): brightness changes apply live and touch nothing else

The display service's hot reload applies a saved brightness within a few
seconds, and /config/main no longer resets other display settings on a
brightness-only JSON body.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(changelog): automatic update hardening

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(config): rewrite PLUGIN_CONFIG_ARCHITECTURE for the v3 web UI

It described web_interface_v2.py and index_v2.html (both gone), client-side
form generation, one POST per field with {key, value}, and 'no nested
objects'. The v3 UI renders plugin forms server-side from the schema
(pages_v3 partial + plugin_config.html macros, nested sections and
x-widgets), posts the whole form once, and save_plugin_config() merges onto
the stored section, validates, splits x-secret fields and notifies the
plugin.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(mqtt): brightness saves apply via hot reload and leave other settings alone

The bridge README said brightness is applied on the display's next
restart; the display controller's config hot reload applies it within
seconds. It also now states that the bridge's partial JSON save changes
only brightness (the /config/main merge fix in this change set).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(update): don't log pip's output from the health check's reinstall

pip can echo a private index URL with embedded credentials;
permission_utils redacts it, the stdlib-only verifier cannot, so it
logs the exit code only.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(config): mark the plugin_system toggles as unused legacy keys

auto_discover, auto_load_enabled and development_mode are read by
nothing and leave the General tab in this change set (F40). CONFIG_REFERENCE
said they were read by the plugin loader; PLUGIN_CONFIGURATION_GUIDE and
the REST reference listed them as live settings.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(changelog): docs and developer tools group

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): legacy plugin-system toggles no longer count as a General save

auto_discover, auto_load_enabled and development_mode have left the General
form, so a post carrying only one of them is not a general-settings save and
must not treat web_display_autostart and auto_update as unchecked. The
plugin_system block itself is left as on main for the branch that reworks it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(changelog): config-save and plugin-config preparation fixes

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(claude): re-check matrix_support.py rules when the library submodule is bumped

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix: address Codacy findings on the core audit PR

- plugin_manager.prepare_plugin_config: when the fallback legacy-boolean
  pass also fails, log a warning instead of a bare except/pass.
- api_client.js: request() refuses any endpoint that is not a plain path
  under /api/v3 ("//host", backslashes, ".." or "." segments, whitespace,
  control characters) with INVALID_ENDPOINT before calling fetch(), and
  plugin ids are URL-encoded wherever they are put into a URL (also in the
  app-shell batch load).
- test_update_all.js: pins both against the shipped client.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): check endpoint control characters without a control-character regex

Codacy (ESLint no-control-regex, Biome noControlCharactersInRegex) flags
the \x00-\x1f range in checkEndpoint's regex. Test the char codes
instead; the endpoints refused are unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* test(auto-update): make the seed script executable on disk, not only in the index

On Linux Repo.publish() commits with -a, which recorded scripts/run.sh
as 100644 upstream because the seed file was never chmod +x. The pull
then brought in the same mode the installer chmod had made locally, so
installer_chmod saw no mode change left to check. The updater was fine:
with the upstream commit at 100755 the --autostash carries the device's
chmod across. Verified under Linux (WSL, git 2.43): the old helper fails
exactly as CI did, the fixed one passes all 63 tests in the file.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

src/common/permission_utils.py

@@ -373,6 +373,14 @@ def sudo_remove_directory(path: Path, allowed_bases: Optional[list] = None) -> b
         return False
 
 
+#: What sudo prints when it refuses a command line outright (not in sudoers for
+#: that exact argv, or it wants a password). Only then is another bash path
+#: worth trying: after pip itself ran, a retry just repeats the failure. The
+#: automatic update's health check keeps its own copy of this list
+#: (scripts/utils/auto_update_verify.py runs without importing src/).
+SUDO_REFUSAL_PHRASES = ("a password is required", "is not allowed to run", "no tty present")
+
+
 def install_requirements_file(req_file: Path, timeout: int = 300) -> subprocess.CompletedProcess:
     """
     Install a requirements.txt file for a plugin (or the project itself).
@@ -434,10 +442,7 @@ def install_requirements_file(req_file: Path, timeout: int = 300) -> subprocess.
             # Distinguish "sudo rejected this exact command line" (worth
             # trying the next bash candidate) from "sudo ran it but pip
             # itself failed" (a real error — stop and surface it).
-            denied = any(
-                phrase in result.stderr
-                for phrase in ("a password is required", "is not allowed to run", "no tty present")
-            )
+            denied = any(phrase in result.stderr for phrase in SUDO_REFUSAL_PHRASES)
             if not denied:
                 # Deliberately don't interpolate req_file or the pip output here:
                 # this log line is scanner-visible, and a static analyzer can't

src/common/scroll_config.py

@@ -22,12 +22,27 @@ shimmer) or repeat frames (which reads as judder). :func:`resolve` warns when
 the requested speed will not divide evenly, because that is a real display
 artefact and not a rounding detail.
 
-Speed is always expressed to the helper as pixels per second and applied in
-time-based mode. Frame-based stepping gates motion on a wall clock at
-``1/scroll_delay`` steps per second; plugins set ``scroll_delay`` to the frame
-period, which puts that comparison exactly on its own threshold and makes the
-step count flip on sub-millisecond jitter. Accumulating elapsed time keeps
-position proportional to real time instead.
+How the speed is applied
+------------------------
+:func:`configure` snaps the requested speed to a :class:`CrispSpeed` -- a whole
+number of pixels per presented frame, with each frame held for ``frame_hold``
+panel refreshes -- and puts the helper in fixed-step mode
+(``ScrollHelper.set_pixels_per_frame``). In that mode the helper consults no
+clock: every ``update_scroll_position()`` call moves exactly that many pixels.
+``SwapOnVSync`` blocks until the panel has taken each frame, so the frame count
+is the clock, and the speed on the panel is::
+
+    px/s = refresh_hz / frame_hold * pixels_per_frame
+
+That makes the hold part of the speed. The caller must pass
+``settings.frame_hold`` to ``display_manager.set_scrolling_state(True, ...)``;
+a caller that omits it is presented every refresh and scrolls ``frame_hold``
+times too fast. The refresh is the panel's (``display_manager.refresh_hz``,
+i.e. ``display.hardware.limit_refresh_rate_hz``) -- never the global
+``target_fps``, which no longer paces anything.
+
+With ``snap_to_crisp=False`` there is no fixed step: the helper is set to
+px/s and advances by elapsed time, and the hold is 1.
 """
 
 from __future__ import annotations
@@ -330,17 +345,18 @@ def configure(
 ) -> ScrollSettings:
     """Resolve the config and apply it to ``scroll_helper``.
 
-    Applied in time-based mode: see the module docstring for why frame-based
-    stepping is not used. ``hasattr`` guards keep this usable against older
-    ScrollHelper builds that a plugin may be running on.
+    Frame-based mode is switched off, the (snapped) speed is set, and with
+    ``snap_to_crisp`` the helper steps a fixed whole-pixel amount per presented
+    frame -- see the module docstring. ``hasattr`` guards keep this usable
+    against older ScrollHelper builds that a plugin may be running on.
 
     :param display_manager: consulted for the panel's refresh rate only (it can
         see display.hardware; a plugin cannot). The frame hold is NOT applied
         here -- see the note in the body. The caller must pass
         ``settings.frame_hold`` to ``display_manager.set_scrolling_state(True,
-        ...)`` when it starts scrolling, or a sub-refresh speed still presents
-        a new frame every refresh and the motion falls back to fractional
-        pixels.
+        ...)`` when it scrolls. The helper moves its fixed step on every call,
+        so without the hold each step is presented every refresh and the
+        scroll runs ``frame_hold`` times faster than the resolved speed.
     :param snap_to_crisp: move the requested speed to the nearest speed the
         panel can show in whole pixels. On by default because a speed that does
         not divide evenly has no good rendering, only a choice of artefacts.
@@ -357,7 +373,8 @@ def configure(
     # refresh to fill in target_fps, pixels_per_frame and the judder warning,
     # so deriving it afterwards described a 100Hz panel to everyone running at
     # 60 -- and with snap_to_crisp=False nothing downstream corrected it, so
-    # set_target_fps() paced the helper to 100 FPS on a 60Hz panel.
+    # the settings and the helper's (informational) target_fps said 100 FPS on
+    # a 60Hz panel.
     hz = _coerce(refresh_hz)
     if hz is None and display_manager is not None:
         hz = _coerce(getattr(display_manager, "refresh_hz", None))
@@ -399,6 +416,9 @@ def configure(
     if hasattr(scroll_helper, "set_pixels_per_frame"):
         scroll_helper.set_pixels_per_frame(
             choice.pixels_per_frame if choice else None)
+    # Informational only: nothing in the helper paces off target_fps. It is
+    # still recorded because plugins read it back (ledmatrix-elections'
+    # test_scroll_pacing.py asserts it equals the crisp presentation rate).
     if choice and hasattr(scroll_helper, "set_target_fps"):
         scroll_helper.set_target_fps(choice.frames_per_second)
     elif settings.target_fps and hasattr(scroll_helper, "set_target_fps"):

src/common/scroll_helper.py

@@ -22,13 +22,6 @@ from typing import Optional, Dict, Any
 from PIL import Image
 import numpy as np
 
-# Try to import scipy for sub-pixel interpolation, fallback to simpler method if not available
-try:
-    from scipy.ndimage import shift
-    HAS_SCIPY = True
-except ImportError:
-    HAS_SCIPY = False
-
 
 # How often the frame-stats line is emitted, and therefore also the ceiling
 # on a believable frame time: a scroll that renders at all cannot take this
@@ -138,21 +131,22 @@ class ScrollHelper:
         # blend (blur) or repeat frames (judder); blending is the worse of the
         # two here. Vegas mode still opts in via set_sub_pixel_scrolling().
         self.sub_pixel_scrolling = False
-        self._last_integer_position = 0  # Cache for integer position to avoid repeated calculations
-        
+
         # Frame-based scrolling settings
         self.frame_based_scrolling = False
         #: Whole pixels to advance per presented frame, or None to pace
         #: off elapsed time. See set_pixels_per_frame.
-        self.fixed_pixels_per_frame = None  # If True, use scroll_delay to throttle and move scroll_speed pixels
-        self.last_step_time = 0.0  # Track last step time for frame-based throttling
-        
+        self.fixed_pixels_per_frame = None
+        self.last_step_time = 0.0  # Time of the last position update
+
         # Time tracking for scroll updates
         self.last_update_time: Optional[float] = None
-        
-        # High FPS settings
-        self.target_fps = 120  # Target 120 FPS for smooth scrolling
-        self.frame_time_target = 1.0 / self.target_fps
+
+        #: Informational only: the presentation rate scroll_config chose
+        #: (panel refresh / frame hold). Nothing paces off it -- the helper
+        #: steps per call and SwapOnVSync paces the calls. Kept because
+        #: plugins and their tests read it back.
+        self.target_fps = 120
         
         # Dynamic duration settings
         self.dynamic_duration_enabled = True
@@ -288,7 +282,14 @@ class ScrollHelper:
     
     def update_scroll_position(self) -> None:
         """
-        Update scroll position with high FPS control and handle wrap-around.
+        Advance the scroll by one presented frame and handle wrap-around.
+
+        With a fixed per-frame step (set_pixels_per_frame, which
+        scroll_config.configure sets for a crisp speed) every call moves
+        exactly that many pixels and no clock is read; the caller's
+        vsync-blocking swap, held for ``frame_hold`` refreshes, sets the rate.
+        Otherwise the position advances by elapsed time at the configured
+        speed.
         """
         if not self.cached_image:
             return
@@ -461,10 +462,9 @@ class ScrollHelper:
         Linear blend between the frames at ``start_x`` and ``start_x + 1``.
 
         Implemented with numpy rather than scipy.ndimage.shift: scipy is not
-        installed on the target devices (HAS_SCIPY is False there), which is why
-        the pre-existing sub-pixel path was dead code — get_visible_portion never
-        consulted the flag, and the scipy fallback would not have interpolated
-        anyway.
+        installed on the target devices, and the old scipy-based sub-pixel path
+        was dead code -- get_visible_portion never consulted the flag. The scipy
+        import was removed with it; installing scipy has no effect.
 
         Args:
             start_x: Left column of the earlier of the two frames
@@ -830,11 +830,13 @@ class ScrollHelper:
     
     def set_scroll_speed(self, speed: float) -> None:
         """
-        Set the scroll speed.
-        
-        In time-based mode: pixels per second (typically 10-200)
-        In frame-based mode: pixels per frame (typically 0.5-5 for smooth scrolling)
-        
+        Set the scroll speed, and leave fixed-step mode.
+
+        In time-based mode: pixels per second (clamped to 1-500).
+        In frame-based mode: pixels per ``scroll_delay`` seconds (clamped to
+        0.1-5), still applied by elapsed time as scroll_speed / scroll_delay
+        px/s.
+
         Args:
             speed: Scroll speed (interpretation depends on frame_based_scrolling mode)
         """
@@ -896,14 +898,19 @@ class ScrollHelper:
 
     def set_target_fps(self, fps: float) -> None:
         """
-        Set the target frames per second for scrolling.
-        
+        Record the presentation rate, for diagnostics only.
+
+        Nothing paces off this value: with a fixed per-frame step the helper
+        advances once per call, and without one it advances by elapsed time.
+        The rate frames are shown at is the panel refresh divided by the frame
+        hold passed to ``display_manager.set_scrolling_state``. scroll_config
+        sets it to that rate so it can be read back.
+
         Args:
-            fps: Target FPS (typically 30-200, default 120)
+            fps: Frames per second (clamped to 30-200)
         """
         self.target_fps = max(30.0, min(200.0, fps))
-        self.frame_time_target = 1.0 / self.target_fps
-        self.logger.debug(f"Target FPS set to: {self.target_fps} FPS (frame_time_target: {self.frame_time_target:.4f}s)")
+        self.logger.debug("Target FPS recorded: %s FPS (informational)", self.target_fps)
     
     def set_sub_pixel_scrolling(self, enabled: bool) -> None:
         """
@@ -914,7 +921,7 @@ class ScrollHelper:
         When disabled, uses integer pixel positioning (faster but may skip pixels).
         
         Args:
-            enabled: True to enable sub-pixel scrolling (default: True)
+            enabled: True to enable sub-pixel scrolling (default: False)
         """
         self.sub_pixel_scrolling = enabled
         self.logger.debug(f"Sub-pixel scrolling {'enabled' if enabled else 'disabled'}")
@@ -923,10 +930,12 @@ class ScrollHelper:
         """
         Enable or disable frame-based scrolling.
         
-        When enabled, update_scroll_position() respects scroll_delay and moves
-        scroll_speed pixels per step. This provides a "stepped" look similar to
-        traditional tickers and can be visually smoother on LED matrices.
-        
+        This does not step. When enabled, ``scroll_speed`` is read as pixels
+        per ``scroll_delay`` seconds (set_scroll_speed clamps it to 0.1-5), and
+        update_scroll_position() still advances by elapsed time at
+        ``scroll_speed / scroll_delay`` px/s. A fixed per-frame step set by
+        set_pixels_per_frame() takes precedence over both modes.
+
         Args:
             enabled: True to enable frame-based scrolling (default: False)
         """
@@ -985,11 +994,7 @@ class ScrollHelper:
         # the real stall rates being measured, so the number could not be
         # trusted at all. Seed the clock and take no sample.
         if self.last_frame_time is None:
-            self.last_frame_time = current_time
-            # Restart the window with the scroll. Otherwise the boundary is
-            # already long overdue when the second frame arrives, and the new
-            # scroll opens by reporting a window of exactly one frame.
-            self.last_fps_log_time = current_time
+            self._restart_stats_window(current_time)
             return
 
         # Calculate instantaneous frame time
@@ -998,9 +1003,10 @@ class ScrollHelper:
         # A caller that scrolls without ever calling reset_scroll() never arms
         # the sentinel above, so catch the same gap by its size. Nothing that
         # renders a scroll produces a frame longer than the log interval; a
-        # sample that large is an idle period, not a frame.
+        # sample that large is an idle period, not a frame. It starts a new
+        # scroll exactly as the sentinel does, window timer included.
         if frame_time >= FPS_LOG_INTERVAL:
-            self.last_frame_time = current_time
+            self._restart_stats_window(current_time)
             return
 
         self.frame_times.append(frame_time)
@@ -1034,7 +1040,17 @@ class ScrollHelper:
 
         self.last_frame_time = current_time
         self.frame_count += 1
-    
+
+    def _restart_stats_window(self, current_time: float) -> None:
+        """Seed the frame clock at the start of a scroll, taking no sample.
+
+        The window timer restarts with it. Otherwise the 5s boundary is
+        already long overdue when the next frame arrives, and the new scroll
+        opens by reporting a window of exactly one frame.
+        """
+        self.last_frame_time = current_time
+        self.last_fps_log_time = current_time
+
     def clear_cache(self) -> None:
         """
         Clear the cached scrolling image.

src/common/sports_scroll.py

@@ -18,10 +18,15 @@ Promoting the content layer would be exactly the mistake
 ``docs/SPORTS_UNIFICATION.md`` warns against — merging on the intuition that
 same-named methods are the same method. Same name, different job.
 
-The one behavior this module adds over the plugin copies is native support for
-``global_config['target_fps']``: the bundled copies hardcode ~100 FPS via
-``scroll_delay=0.01`` and never consult the global smooth-scrolling target. A
-plugin inheriting from here gets it for free.
+What this module adds over the plugin copies is pacing through
+:mod:`src.common.scroll_config`, the resolver every other scroller uses: the
+configured px/s is snapped to a whole-pixel speed for the panel's refresh, the
+helper steps a fixed number of pixels per presented frame, and each drawn frame
+publishes the frame hold to the display manager. Speed depends only on
+``scroll_speed`` and the panel refresh
+(``display.hardware.limit_refresh_rate_hz``) -- not on the global
+``target_fps``, and not on ``scroll_delay``, which is kept in the settings for
+compatibility only.
 
 Usage::
 
@@ -94,9 +99,9 @@ class SportsScrollDisplay:
         :param display_manager: the core display manager
         :param config: the plugin's configuration
         :param custom_logger: the plugin's logger, so scroll lines are attributed
-        :param global_config: the LEDMatrix global config — the source of
-            ``target_fps``. Optional so an older caller that does not pass it
-            keeps working at the config-derived pacing.
+        :param global_config: the LEDMatrix global config, consulted for the
+            panel refresh when the display manager cannot report one.
+            Optional so an older caller that does not pass it keeps working.
         """
         self.display_manager = display_manager
         self.config = config
@@ -196,21 +201,6 @@ class SportsScrollDisplay:
                 return {**settings, **override}
         return settings
 
-    def _resolve_target_fps(self) -> Optional[float]:
-        """The global smooth-scrolling FPS target, or None to keep config pacing.
-
-        Coerced before use: a malformed value in the global config must degrade
-        to the existing ``scroll_delay`` pacing, never raise on a display path.
-        """
-        raw = self.global_config.get("target_fps") or self.global_config.get(
-            "scroll_target_fps"
-        )
-        try:
-            return float(raw) if raw is not None else None
-        except (TypeError, ValueError):
-            self.logger.debug("Ignoring unusable target_fps: %r", raw)
-            return None
-
     def _coerce_float(self, value: Any, default: float) -> float:
         """A usable float from config, or ``default``.
 
@@ -246,8 +236,8 @@ class SportsScrollDisplay:
         # settings dict: the two read the same key names with different
         # meanings, and the collision is a factor of 1/scroll_delay.
         #
-        #   sports_scroll: scroll_speed is px/SECOND; scroll_delay is only the
-        #                  frame period used to reach px/frame.
+        #   sports_scroll: scroll_speed is px/SECOND; scroll_delay is ignored
+        #                  for pacing (see _resolve_pixels_per_second).
         #   scroll_config: scroll_speed is px per STEP, so px/s = speed/delay.
         #
         # Passing {"scroll_speed": 50.0, "scroll_delay": 0.01} straight through
@@ -276,8 +266,13 @@ class SportsScrollDisplay:
     def _resolve_pixels_per_second(self, settings: Dict[str, Any]) -> float:
         """This module's config shape, expressed as plain pixels per second.
 
-        ``scroll_speed`` is already px/s here. ``scroll_delay`` only matters
-        when a caller supplied px/frame instead, which the 0 case covers.
+        ``scroll_speed`` is already px/s here, and it is the whole answer.
+        ``scroll_delay`` is kept in the settings for compatibility but is
+        ignored for pacing: the frame rate is the panel refresh divided by the
+        frame hold scroll_config picks, so no positive delay changes the speed.
+        The one exception is a delay of exactly 0 (below every scoreboard
+        schema's minimum), which is read as ``scroll_speed`` being px per
+        frame at ``ASSUMED_FPS_WHEN_UNPACED``.
         """
         scroll_speed = self._coerce_float(settings.get("scroll_speed"), 50.0)
         scroll_delay = self._coerce_float(settings.get("scroll_delay"), 0.01)
@@ -285,19 +280,29 @@ class SportsScrollDisplay:
             return scroll_speed * ASSUMED_FPS_WHEN_UNPACED
         return scroll_speed
 
-    def _resolve_refresh_hz(self) -> Optional[float]:
+    def _resolve_refresh_hz(self) -> float:
         """The panel refresh the crisp ladder should be computed against.
 
-        Prefers the configured hardware refresh. Falls back to the global
-        ``target_fps``/``scroll_target_fps`` this module has always honoured:
-        under the old model that key *was* the rate frames were presented at,
-        so it is the faithful translation for anyone who set it. Returning
-        None lets scroll_config apply its own default.
+        This has to be the rate frames are actually presented at, because the
+        helper advances a fixed number of whole pixels per presented frame and
+        the display manager holds each frame for ``frame_hold`` refreshes. A
+        ladder built for any other rate plays back at the wrong speed: built
+        for 60 Hz and shown on a 100 Hz panel, it runs 100/60 too fast.
+
+        So it is the display manager's ``refresh_hz`` (what the panel is
+        driven at), then ``display.hardware.limit_refresh_rate_hz`` from the
+        global config, then scroll_config's default. The global ``target_fps``
+        is deliberately NOT consulted: before frame-locked presentation it was
+        the rate frames were shown at, but now honouring it only turned the
+        General tab's "Scroll Frame Rate" into a scoreboard speed multiplier.
         """
-        hardware = scroll_config.refresh_hz_from_config(self.global_config)
-        if hardware and hardware != scroll_config.DEFAULT_REFRESH_HZ:
-            return hardware
-        return self._resolve_target_fps() or hardware or None
+        reported = getattr(self.display_manager, "refresh_hz", None)
+        # A real number only: a stub or a mock answering for anything must not
+        # become the refresh rate.
+        if (isinstance(reported, (int, float)) and not isinstance(reported, bool)
+                and reported > 0):
+            return float(reported)
+        return scroll_config.refresh_hz_from_config(self.global_config)
 
     def _scroll_frame_hold(self) -> int:
         """Refreshes to hold each frame for, from the resolved settings."""
@@ -327,11 +332,12 @@ class SportsScrollDisplay:
                 return False
 
             # Tell the core the panel is scrolling, and for how many
-            # refreshes to hold each frame. Without this the frame hold is
-            # never applied -- so a speed the ladder made crisp still presents
-            # a new frame every refresh and judders -- and, because deferred
-            # updates only run while nothing is scrolling, core would run
-            # blocking work in the middle of this scroll.
+            # refreshes to hold each frame. The helper advances a fixed number
+            # of whole pixels per presented frame, so without the hold a new
+            # frame is presented every refresh and the scroll runs frame_hold
+            # times too fast. And because deferred updates only run while
+            # nothing is scrolling, core would otherwise run blocking work in
+            # the middle of this scroll.
             if hasattr(self.display_manager, "set_scrolling_state"):
                 self.display_manager.set_scrolling_state(
                     True, frame_hold=self._scroll_frame_hold())