refactor: remove client-side cache key pulls

app/javascript/dashboard/api/CacheEnabledApiClient.js

@@ -50,12 +50,11 @@ class CacheEnabledApiClient extends ApiClient {
       return this.getFromNetwork();
     }
 
-    // Trust the IDB cache. Freshness is maintained by:
-    //   - boot-time hydrateStoresFromCache (compares server keys once on boot)
-    //   - ActionCable ACCOUNT_CACHE_INVALIDATED broadcasts (live updates)
-    //   - ReconnectService.revalidateCaches (on WebSocket reconnect)
-    // Skipping the per-call /cache_keys preflight eliminates N GET requests per
-    // cold settings-page load.
+    // Trust the IDB cache. Freshness is maintained by the
+    // account.cache_invalidated event alone: RoomChannel pushes the cache-key
+    // map on every (re)subscribe — boot and reconnect included — and the
+    // server broadcasts it on every change. Skipping a per-call /cache_keys
+    // preflight eliminates N GET requests per cold settings-page load.
     const localData = await this.dataManager.get({
       modelName: this.cacheModelName,
     });

app/javascript/dashboard/api/account.js

@@ -9,13 +9,6 @@ class AccountAPI extends ApiClient {
   createAccount(data) {
     return axios.post(`${this.apiVersion}/accounts`, data);
   }
-
-  async getCacheKeys() {
-    const response = await axios.get(
-      `/api/v1/accounts/${this.accountIdFromRoute}/cache_keys`
-    );
-    return response.data.cache_keys;
-  }
 }
 
 export default new AccountAPI();