chore: delete unreferenced scripts and archived docs; fix stale doc claims (#607)

* chore(scripts): delete unreferenced helper scripts

None of these is referenced by an installer, systemd unit, CI workflow,
test, the web UI or src/:

- utils/cleanup_venv.sh removes venv_web_v2, which nothing creates
- utils/clear_python_cache.sh hardcodes ~/LEDMatrix and a .webassets-cache
  nothing uses
- install/migrate_config.sh only copies the template, which the installer
  and ConfigManager already do
- install/debug_install.sh, debug/debug_web_manual.py
- diagnose_web_ui.sh and verify_web_ui.sh overlap diagnose_web_interface.sh,
  which the docs point to
- fix_internet_connectivity.sh is iptables-only (stale on nftables)
- diagnose_plugin_permissions.sh, dev/validate_python.py
- download_nba_logos.py + README_NBA_LOGOS.md: logo_downloader fetches
  logos on demand
- setup_plugin_repos.py linked into the production plugin-repos/ dir; the
  dev workflow is scripts/dev/dev_plugin_setup.sh, and
  MULTI_ROOT_WORKSPACE_SETUP.md now uses it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* chore(config): drop unused plugin_system flags and a dead unit comment

- config.template.json: remove plugin_system.auto_discover,
  auto_load_enabled and development_mode. Nothing reads them; the web UI
  only stores them when a client sends them. ConfigManager's migration
  only adds template keys, so existing configs keep theirs unchanged.
- config.template.json: re-indent vegas_scroll's live_* keys.
- systemd/ledmatrix.service: remove the comment documenting
  LEDMATRIX_ON_DEMAND_PLUGIN / on_demand_env.conf; nothing reads either.
- CONFIG_REFERENCE.md: say the legacy keys are no longer in the template.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: delete docs/archive and PLUGIN_IMPLEMENTATION_SUMMARY.md

- docs/archive/: superseded guides; the repository history keeps them
  and no live doc links into the directory. The one open document in it,
  WEB_UI_AUDIT_2026-09.md, moves to docs/audits/ and is linked from the
  docs index.
- PLUGIN_IMPLEMENTATION_SUMMARY.md invented usage statistics, called
  v2.0.0 current, listed shipped auto-updates as future work and
  documented a BasePlugin.get_config() that does not exist.
- docs/README.md: drop both, and stop telling contributors to archive
  obsolete pages instead of deleting them.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(plugin-api): fix extra_small_font size, cache metric key and scroll pacing example

- PLUGIN_API_REFERENCE: extra_small_font loads at 7, not 6 (crisp_size
  snaps it, src/display_manager.py); get_cache_metrics() returns
  cache_hit_rate, not hit_rate (src/cache/cache_metrics.py).
- ADVANCED_PLUGIN_DEVELOPMENT: the basic scrolling example slept in a loop
  and never passed frame_hold; use ScrollHelper + scroll_config.configure()
  and set_scrolling_state(True, frame_hold=...) as PLUGIN_API_REFERENCE does.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(plugin-config): match the config tab, icon and web-action docs to the code

- PLUGIN_CONFIG_QUICK_START / PLUGIN_CONFIGURATION_TABS /
  PLUGIN_CONFIGURATION_GUIDE: there is no "Reset to Defaults" button (the
  tab has Refresh, Update, Uninstall, Save Configuration); plugin config
  hot-reloads (ConfigService + on_config_change), so no restart; the
  schema is found by the fixed name config_schema.json, not a manifest
  config_schema field; the tab row is "Plugin Manager", not "Plugins";
  forms are server-rendered from /v3/partials/plugin-config/<id>; the
  duration hook is get_display_duration()/display_duration; a class_name
  mismatch raises PluginError; the store requires id, name, class_name and
  display_modes (not version); plugin_system.debug/log_level do not exist
  (use run.py -d / LEDMATRIX_DEBUG). Drop "future" features that shipped.
- PLUGIN_CONFIG_CORE_PROPERTIES: list all of CORE_PLUGIN_PROPERTIES,
  including skin, skin_options and the vegas_* tuning keys.
- PLUGIN_CUSTOM_ICONS: icon is only a Font Awesome class (fallback
  fa-puzzle-piece); emoji/URL icons and getPluginIcon() never existed in
  v3. Note that /api/v3/plugins/installed currently omits icon.
- PLUGIN_WEB_UI_ACTIONS (+ example JSON): success_message, error_message
  and step1_message are never read.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(store): describe the monorepo registry and the store UI as they are

- PLUGIN_STORE_GUIDE: the Plugin Store is a section of the Plugin
  Manager tab; URL installs are "Install from GitHub" -> "Install Single
  Plugin"; bulk update exists (Check & Update All) plus opt-in weekly
  auto-update; PluginStoreManager() defaults to plugins/, so the Python
  examples pass plugin-repos; registry plugins are downloaded (GitHub API,
  ZIP fallback), not cloned; updates compare version with latest_version.
- PLUGIN_REGISTRY_SETUP_GUIDE: replace the per-plugin-repo + tag
  walkthrough with a short page on the monorepo registry (plugin_path,
  latest_version, update_registry.py) that points at the monorepo's own
  SUBMISSION.md. Drops the reference to the deleted
  PLUGIN_IMPLEMENTATION_SUMMARY.md and setup_plugin_repos.py.
- plugin_registry_template.json: use the real entry shape.
- PLUGIN_QUICK_REFERENCE: automatic background updates exist (opt-in);
  registry example and publishing steps use the monorepo, not tags.
- PLUGIN_DEVELOPMENT_GUIDE: tags/releases are not read by the store.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(readme): fix the Triple Bonnet mapping, install prerequisites and backup names

- README: the Adafruit Triple Bonnet uses `regular` (3 outputs), not
  `regular-pi1` (1 output) -- src/matrix_support.py MAPPING_OUTPUTS, and
  the README's own hardware_mapping section; the template default mapping
  is adafruit-hat, the PWM mod switches it to adafruit-hat-pwm; manual
  install only needs git up front (first_time_install.sh installs
  python-dev-is-python3, cmake, ninja-build etc.; cython3/scons are not
  used); the Pi Zero 2 W is a supported low-memory board, consistent with
  PRODUCT.md, LOW_MEMORY_BOARDS.md and the installer's low-memory build;
  fix the "First_time_install.sh" spelling, an orphan "2." list item and
  the hello-world starter link (it lives in the plugins monorepo).
- CONFIG_DEBUGGING: automatic backups are
  config/backups/config.json.backup.<YYYYMMDD_HHMMSS_ffffff> (five kept),
  not config_YYYYMMDD_HHMMSS.json.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(dev): correct the test-running and rgbmatrix build instructions

- HOW_TO_RUN_TESTS: coverage is not collected by a plain pytest run and
  pytest.ini has no threshold; the only one is --cov-fail-under=52 in the
  core unit-test job of .github/workflows/test.yml, which runs the whole
  test/ tree (not an allowlist). Almost no tests carry markers, so
  -m integration / -m slow select nothing; drop them and -m unit as the
  quick check. Replace the hardcoded /home/chuck path.
- DEVELOPMENT: the rgbmatrix package is built with pip install . from
  the submodule root (scikit-build-core + CMake + Ninja), as
  first_time_install.sh does; there is no make build-python /
  bindings/python step, and the build deps are python-dev-is-python3,
  cmake and ninja-build, not cython3/scons.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(wifi): the setup AP is open; auto-enable can be turned off without code changes

- WIFI_NETWORK_SETUP / SSH_UNAVAILABLE_AFTER_INSTALL: both AP paths in
  src/wifi_manager.py create an open network and nothing reads
  ap_password, so drop the "ledmatrix123" password and the ap_password
  key/advice.
- SSH_UNAVAILABLE_AFTER_INSTALL: disabling automatic AP mode does not
  need code changes -- auto_enable_ap_mode is a WiFi-tab toggle and
  POST /api/v3/wifi/ap/auto-enable; note the monitor daemon reads
  wifi_config.json at start, so restart it after changing the setting.
  Use the ledpi username and a relative install path like the other docs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(reference): add auto_update, drop drifted line numbers, fix UI and service details

- CONFIG_REFERENCE: document the top-level auto_update.enabled key (read
  by web_interface/auto_update.py and src/auto_update_setup.py); replace
  drifted file:line references with function names; the template's
  dim_schedule mode is "global".
- ADVANCED_FEATURES: core does not read a per-plugin background_service
  block (the sports plugins read their own), and priority is "higher
  number = higher priority" on FetchRequest but not used for ordering.
- WEB_INTERFACE_GUIDE: the General tab toggle is "Web Display Autostart"
  (web interface service), brightness is 1-100, and config paths are
  relative to the LEDMatrix folder, not /config.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: drop references to code removed in #608

get_installed_plugin_info, WiFiManager's saved_networks and the six
always-skipping plugin test files are deleted there. NetworkManager already
remembers joined networks; LEDMatrix no longer stores WiFi passwords.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: don't link SKIN_SYSTEM.md from the core-properties page

#615 deletes SKIN_SYSTEM.md; with this link, whichever of the two merged
second would break test_doc_links. The skin/skin_options entries go when
#615 removes the keys.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/ADVANCED_FEATURES.md

@@ -886,7 +886,13 @@ Cache Check → Background Fetch → Partial Data → Completion → Cache
 
 ### Configuration
 
-Enable background service per plugin in `config/config.json`:
+Core does not read a `background_service` config block: the service itself
+(`src/background_data_service.py`) is a process-wide singleton, and its
+worker count is whatever the first caller of `get_background_service()`
+passes. The sports scoreboard plugins read their own
+`background_service` settings and pass them to it, so the exact keys and
+where they sit (top level or per league) are defined by each plugin's
+`config_schema.json`. A typical block looks like:
 
 ```json
 {
@@ -907,11 +913,11 @@ Enable background service per plugin in `config/config.json`:
 
 | Setting | Default | Description |
 |---------|---------|-------------|
-| `enabled` | `false` | Enable background service for this plugin |
+| `enabled` | plugin-defined | Use the background service for this plugin's fetches |
 | `max_workers` | `3` | Max concurrent background tasks |
 | `request_timeout` | `30` | Timeout per API request (seconds) |
 | `max_retries` | `3` | Retry attempts on failure |
-| `priority` | `1` | Task priority (1=highest, 10=lowest) |
+| `priority` | `1` | Stored on each request (higher number = higher priority, per `FetchRequest`), but the service runs requests in submission order; it does not reorder by priority |
 
 ### Performance Impact
 
@@ -928,9 +934,9 @@ Enable background service per plugin in `config/config.json`:
 
 The background data service is used by all of the sports scoreboard
 plugins (football, hockey, baseball/MLB, basketball, soccer, lacrosse,
-F1, UFC), the odds ticker, and the leaderboard plugin. Each plugin's
-`background_service` block (under its own config namespace) follows the
-same shape as the example above.
+F1, UFC), the odds ticker, and the leaderboard plugin. Each plugin reads
+its own `background_service` block (under its own config namespace); check
+that plugin's `config_schema.json` for the keys it accepts.
 
 ### Error Handling & Fallback