fix(plugins): store and plugin-manager bugs; tidy src/plugin_system (#635)

* fix(store): don't read a ZIP-installed plugin's remote from the LEDMatrix repo

update_plugin looked up remote.origin.url with `git -C <plugin> config
--local` for plugins that are not git checkouts. Under plugin-repos/ git
walks up to the enclosing LEDMatrix repository, so the lookup returned
LEDMatrix's own URL and a plugin missing from the registry was
"reinstalled" from the LEDMatrix repo. Only ask git when the plugin
directory has its own .git, the test _get_local_git_info already uses.

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

* fix(schema): report each missing required field once, by name

validate_config_against_schema ran its own required-fields loop after
Draft7Validator.iter_errors, which already yields one `required` error
per missing field, so every missing top-level field was listed twice.
The validator's copy also printed the schema's whole `required` list
("Missing required property '['api_key', 'city']'") instead of the field.
Drop the loop and take the field name from the error itself.

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

* fix(store): stop mangling repository URLs that contain ".git"

install_from_url and fetch_registry_from_url cleaned URLs with
`rstrip('/').replace('.git', '')`, which removes ".git" anywhere:
https://github.com/user/my.github.io became .../myhub.io, so installing
or browsing that repository asked GitHub for one that does not exist.

Add src/plugin_system/repo_urls.py with one anchored normalize_repo_url(),
same_repo() for comparisons, github_owner_repo() and github_api_headers(),
and use them for the five copies of the owner/repo parsing and GitHub
headers in the store and for saved repositories. GitHub URLs are now
recognised by urlparse().hostname everywhere: _get_latest_commit_info
used a substring test, and _install_from_monorepo_api parsed any host.

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

* fix(store): install a repository whose only branch is not main/master

_install_via_git returned None both when every clone failed and when the
last-resort clone of the repository's default branch succeeded.
_install_plugin_impl papered over it with `and not plugin_path.exists()`;
install_from_url did not, so a repository whose only branch is e.g.
`develop` was cloned, then treated as a failure, then "downloaded" from
main/master archives that do not exist.

After a default-branch clone, return the branch the clone checked out
(read from .git/HEAD), so None means failure and nothing else, and give
both callers the same `branch_used is None` fallback.

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

* fix(plugins): judge the memory limit on each call's own growth

monitor_call stores `metrics.memory_mb = max(previous, growth)`, and
_check_limits compared that high-water mark with max_memory_mb. It never
decreases, so once one update() grew the process past the limit every
later call raised ResourceLimitExceeded and the circuit breaker kept
reopening. Pass the call's own RSS growth to _check_limits; keep the
high-water mark for reporting and document what it measures.

Remove ResourceMetrics.update_average_execution_time: nothing called it,
and it overwrote the running total with the average.

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

* fix(plugins): reload_plugin re-reads the manifest from the discovered directory

reload_plugin read `plugins_dir / plugin_id / "manifest.json"`, ignoring
the discovery map and the plugin_dirs rules. For a plugin whose
directory name differs from its manifest id the path did not exist, the
re-read was skipped without a word, and the reload kept the stale
manifest. Resolve the directory with find_plugin_directory, as
load_plugin does.

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

* fix(plugins): drop the always-null last_display from plugin state info

PluginStateManager reported `last_display` from `_last_display`, which
nothing ever wrote, so it was null for every plugin. Recording it in
PluginExecutor.execute_display would not help: get_state_info's only
reader is the web process, whose PluginManager never calls display().
Remove the field, its dict and get_last_display() (no caller in core,
the web UI or the plugin monorepo).

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

* refactor(store): share the rollback and requirements helpers, drop dead code

- install_plugin and _reinstall_with_rollback set aside, discard and
  restore the old copy through _set_aside/_discard_backup/_restore_backup
  instead of two copies of the same blocks.
- The loader and the store run the same pre-pip checks through
  contained_plugin_dir() and requirements_to_install() in plugin_loader.
  They still invoke pip differently (sys.executable -m pip vs. the sudo
  wrapper). `except (BrokenPipeError, OSError)` + `isinstance(e, OSError)`
  becomes `except OSError` checking errno.EPIPE.
- load_module never returns None, so load_plugin's check is gone and the
  docstring says what it raises.
- Remove the always-true JSONSCHEMA_AVAILABLE, the inline re-imports of
  re and permission_utils, the fake status_result object nobody reads,
  hasattr(git_error, 'cmd'), a redundant "merge conflict" test and
  `import traceback` (exc_info=True does it).
- Correct comments: install_from_url names the directory for the
  caller's id when given (not always the manifest id), _get_local_git_info
  saves one git subprocess (not four), _enrich calls two helpers,
  search_plugins documents all its arguments, _find_plugin_path states
  its behaviour instead of a TODO, and history narration is gone.

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

* refactor(plugins): tidy base_plugin, correct plugin_manager/state comments

- base_plugin: drop the unused `import logging`; get_display_duration
  runs the instance value and the config value through one
  _positive_seconds() helper instead of two copies of the coercion; the
  'static'/'none'/fallback branches of get_vegas_display_mode, which all
  returned FIXED_SEGMENT, are one; fix the mis-indented validate_config
  example; say that get_supported_vegas_modes/get_vegas_segment_width
  are not consulted by core (kept, plugins override them).
- schema_manager: import expand_style_elements normally rather than
  swallowing an ImportError of a core module.
- plugin_manager: the plugins directory is the configured one
  (plugin-repos/ by default), not plugins/; get_config() returns the live
  dict, not a copy, so the interval cache comments say what it saves.
- state_manager: config_version and the file version are not used to
  detect corruption; say what they are.

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

* refactor(plugins): stop writing data/plugin_operations.json

PluginOperationQueue wrote its finished-operation history to
data/plugin_operations.json after every operation, and read it back only
into its own in-memory list, which only get_operation_history() exposes
-- and nothing calls that. The operation-history endpoint reads
OperationHistory (data/operation_history.json). No code in src/,
web_interface/, scripts/ or test/ reads the file.

Drop the history_file/lazy_load parameters and the load/save code; the
bounded in-memory history stays. web_interface/app.py and the
integration test stop passing the removed arguments. An existing
data/plugin_operations.json is left in place (data/* is gitignored).

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

* docs(changelog): plugin-system

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

---------

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

src/plugin_system/repo_urls.py

@@ -0,0 +1,70 @@
+"""
+Repository URL helpers shared by the plugin store and saved repositories.
+
+One definition of "the same repository URL", of how a GitHub URL maps to
+``owner/repo``, and of the headers sent to the GitHub API.
+"""
+
+from typing import Dict, Optional, Tuple
+from urllib.parse import urlparse
+
+#: Hosts whose URLs name a GitHub repository. Matched against
+#: ``urlparse(url).hostname``, never by substring: a substring test accepts
+#: ``https://github.com.example.org/...`` as GitHub.
+GITHUB_HOSTS = frozenset({'github.com', 'www.github.com'})
+
+#: Sent on every request the store makes to GitHub.
+USER_AGENT = 'LEDMatrix-Plugin-Manager/1.0'
+
+
+def normalize_repo_url(url: str) -> str:
+    """``url`` without surrounding whitespace, trailing slashes or a trailing ``.git``.
+
+    Only a *trailing* ``.git`` is removed. The unanchored
+    ``url.replace('.git', '')`` this replaces turned
+    ``https://github.com/user/my.github.io`` into ``.../myhub.io``.
+    Case is preserved; compare with :func:`same_repo`.
+    """
+    url = url.strip().rstrip('/')
+    if url.endswith('.git'):
+        url = url[:-4]
+    return url
+
+
+def same_repo(url_a: str, url_b: str) -> bool:
+    """Whether two URLs name the same repository.
+
+    GitHub owner and repository names are case-insensitive, so
+    ``ChuckBuilds/LEDMatrix-Plugins`` and ``chuckbuilds/ledmatrix-plugins``
+    are one repository.
+    """
+    return normalize_repo_url(url_a).lower() == normalize_repo_url(url_b).lower()
+
+
+def github_owner_repo(url: str) -> Optional[Tuple[str, str]]:
+    """``(owner, repo)`` for a github.com repository URL, else None.
+
+    The first two path segments, so a URL that points inside the repository
+    (``.../owner/repo/tree/main/plugins/x``) still names ``owner/repo``.
+    """
+    parsed = urlparse(normalize_repo_url(url))
+    if parsed.hostname not in GITHUB_HOSTS:
+        return None
+    parts = [part for part in parsed.path.split('/') if part]
+    if len(parts) < 2:
+        return None
+    return parts[0], normalize_repo_url(parts[1])
+
+
+def github_api_headers(token: Optional[str] = None) -> Dict[str, str]:
+    """Headers for a GitHub REST API request, authenticated when ``token`` is set.
+
+    An authenticated request gets 5000 requests an hour instead of 60.
+    """
+    headers = {
+        'Accept': 'application/vnd.github.v3+json',
+        'User-Agent': USER_AGENT,
+    }
+    if token:
+        headers['Authorization'] = f'token {token}'
+    return headers