fix(plugins): namespace-isolate modules for safe parallel loading (#237)

* fix(plugins): prevent KeyError race condition in module cleanup

When multiple plugins have modules with the same name (e.g.,
background_data_service.py), the _clear_conflicting_modules function
could raise a KeyError if a module was removed between iteration
and deletion. This race condition caused plugin loading failures
with errors like: "Unexpected error loading plugin: 'background_data_service'"

Changes:
- Use sys.modules.pop(mod_name, None) instead of del sys.modules[mod_name]
  to safely handle already-removed modules
- Apply same fix to plugin unload in plugin_manager.py for consistency
- Fix typo in sports.py: rankself._team_rankings_cacheings ->
  self._team_rankings_cache

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(plugins): namespace-isolate plugin modules to prevent parallel loading collisions

Multiple sport plugins share identically-named Python files (scroll_display.py,
game_renderer.py, sports.py, etc.). When loaded in parallel via ThreadPoolExecutor,
bare module names collide in sys.modules causing KeyError crashes.

Replace _clear_conflicting_modules with _namespace_plugin_modules: after exec_module
loads a plugin, its bare-name sub-modules are moved to namespaced keys
(e.g. _plg_basketball_scoreboard_scroll_display) so they cannot collide.
A threading lock serializes the exec_module window where bare names temporarily exist.

Also updates unload_plugin to clean up namespaced sub-modules from sys.modules.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(plugins): address review feedback on namespace isolation

- Fix main module accidentally renamed: move before_keys snapshot to
  after sys.modules[module_name] insertion so the main entry is excluded
  from namespace renaming and error cleanup
- Use Path.is_relative_to() instead of substring matching for plugin
  directory containment checks to avoid false-matches on overlapping
  directory names
- Add try/except around exec_module to clean up partially-initialized
  modules on failure, preventing leaked bare-name entries
- Add public unregister_plugin_modules() method on PluginLoader so
  PluginManager doesn't reach into private attributes during unload
- Update stale comment referencing removed _clear_conflicting_modules

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(plugins): remove unused plugin_dir_str variable

Leftover from the old substring containment check, now replaced by
Path.is_relative_to().

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(plugins): extract shared helper for bare-module filtering

Hoist plugin_dir.resolve() out of loops and deduplicate the bare-module
filtering logic between _namespace_plugin_modules and the error cleanup
block into _iter_plugin_bare_modules().

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(plugins): keep bare-name alias to prevent lazy import duplication

Stop removing bare module names from sys.modules after namespacing.
Removing them caused lazy intra-plugin imports (deferred imports inside
methods) to re-import from disk, creating a second inconsistent module
copy. Keeping both the bare and namespaced entries pointing to the same
object avoids this. The next plugin's exec_module naturally overwrites
the bare entry with its own version.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Chuck <chuck@example.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

src/plugin_system/plugin_manager.py

@@ -415,11 +415,13 @@ class PluginManager:
             if plugin_id in self.plugin_last_update:
                 del self.plugin_last_update[plugin_id]
             
-            # Remove module from sys.modules if present
+            # Remove main module from sys.modules if present
             module_name = f"plugin_{plugin_id.replace('-', '_')}"
-            if module_name in sys.modules:
-                del sys.modules[module_name]
-            
+            sys.modules.pop(module_name, None)
+
+            # Delegate sub-module and cached-module cleanup to the loader
+            self.plugin_loader.unregister_plugin_modules(plugin_id)
+
             # Remove from plugin_modules
             self.plugin_modules.pop(plugin_id, None)