feat(plugins): soft refresh UI des contributions plugins après install/reload — frontend #279 (PluginRuntimeProvider refreshRuntime sur événements pluginInstalled/pluginReloaded, dispose de l'ancien registry, catalogue listRuntimeContributions, gateway mock; QA verte ré-exécutée: 35/35 tests features/plugins dont nouveau PluginRuntimeProvider.test, typecheck OK)

frontend/src/plugins/runtime/loader.ts

@@ -1,7 +1,8 @@
 /**
  * Plugin bootstrap loader (ticket #43, F1, carnet §1.3/§6).
  *
- * At UI bootstrap, the app calls {@link loadPlugins} once with the catalog
+ * At UI bootstrap and after an install/reload event, the app calls
+ * {@link loadPlugins} with the catalog
  * from `PluginGateway.listRuntimeContributions()` (already filtered by the
  * backend to `enabled && !pendingUninstall`, carnet §1.3) and the gateway set
  * used to build the public service facade. For each entry it dynamically imports
@@ -370,9 +371,8 @@ function createPluginStorage(gateways: PluginGatewaySet, pluginId: string): Plug
 
 /**
  * Loads every plugin in the catalog into a fresh {@link PluginRuntimeRegistry}.
- * Called once at app bootstrap (and never again in the same session — carnet
- * §1.3: disable/uninstall only masks contributions in-session, the actual
- * unload happens on next restart via a fresh `loadPlugins` call).
+ * The provider swaps this fresh snapshot atomically at bootstrap and after a
+ * supported plugin lifecycle event.
  */
 export async function loadPlugins(
   catalogPlugins: PluginRuntimePlugin[],