fix: address CodeRabbit review findings across plugin system

- plugin_manager.py: clear plugin_manifests/plugin_directories before update
  to prevent ghost entries for uninstalled plugins persisting across scans
- state_reconciliation.py: remove 'enabled' key check that skipped legacy
  plugin configs, default to enabled=True matching PluginManager.load_plugin
- app.py: add threading.Lock around reconciliation start guard to prevent
  race condition spawning duplicate threads; add -> None return annotation
- store_manager.py: use resolved registry ID (alt_id) instead of original
  plugin_id when reinstalling during monorepo migration
- base.html: check Response.ok in loadPluginsDirect fallback; trigger
  fallback on tab click when HTMX unavailable; remove active-tab check
  from 5-second timeout so content preloads regardless

Skipped: api_v3.py secret redaction suggestion — the caller at line 2539
already tries schema-based mask_secret_fields() before falling back to
_conservative_mask_config, making the suggested change redundant.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/plugin_system/plugin_manager.py

@@ -136,11 +136,14 @@ class PluginManager:
         except (OSError, PermissionError) as e:
             self.logger.error("Error scanning directory %s: %s", directory, e, exc_info=True)
 
-        # Update shared state under lock
+        # Replace shared state under lock so uninstalled plugins don't linger
         with self._discovery_lock:
+            self.plugin_manifests.clear()
             self.plugin_manifests.update(new_manifests)
             if not hasattr(self, 'plugin_directories'):
                 self.plugin_directories = {}
+            else:
+                self.plugin_directories.clear()
             self.plugin_directories.update(new_directories)
 
         return plugin_ids

src/plugin_system/state_reconciliation.py

@@ -182,10 +182,8 @@ class StateReconciliation:
                     continue
                 if plugin_id in self._SYSTEM_CONFIG_KEYS:
                     continue
-                if 'enabled' not in plugin_config:
-                    continue
                 state[plugin_id] = {
-                    'enabled': plugin_config.get('enabled', False),
+                    'enabled': plugin_config.get('enabled', True),
                     'version': plugin_config.get('version'),
                     'exists_in_config': True
                 }

src/plugin_system/store_manager.py

@@ -1785,11 +1785,13 @@ class PluginStoreManager:
                 self.fetch_registry(force_refresh=True)
                 plugin_info_remote = self.get_plugin_info(plugin_id, fetch_latest_from_github=True, force_refresh=True)
                 # Try without 'ledmatrix-' prefix (monorepo migration)
+                resolved_id = plugin_id
                 if not plugin_info_remote and plugin_id.startswith('ledmatrix-'):
                     alt_id = plugin_id[len('ledmatrix-'):]
                     plugin_info_remote = self.get_plugin_info(alt_id, fetch_latest_from_github=True, force_refresh=True)
                     if plugin_info_remote:
-                        self.logger.info(f"Plugin {plugin_id} found in registry as {alt_id}")
+                        resolved_id = alt_id
+                        self.logger.info(f"Plugin {plugin_id} found in registry as {resolved_id}")
                 remote_branch = None
                 remote_sha = None
 
@@ -1804,13 +1806,13 @@ class PluginStoreManager:
                     local_remote = git_info.get('remote_url', '')
                     if local_remote and registry_repo and self._normalize_repo_url(local_remote) != self._normalize_repo_url(registry_repo):
                         self.logger.info(
-                            f"Plugin {plugin_id} git remote ({local_remote}) differs from registry ({registry_repo}). "
+                            f"Plugin {resolved_id} git remote ({local_remote}) differs from registry ({registry_repo}). "
                             f"Reinstalling from registry to migrate to new source."
                         )
                         if not self._safe_remove_directory(plugin_path):
-                            self.logger.error(f"Failed to remove old plugin directory for {plugin_id}")
+                            self.logger.error(f"Failed to remove old plugin directory for {resolved_id}")
                             return False
-                        return self.install_plugin(plugin_id)
+                        return self.install_plugin(resolved_id)
 
                     # Check if already up to date
                     if remote_sha and local_sha and remote_sha.startswith(local_sha):