feat: split asset_update_options_enabled into separate deletion and rename flags (#7864)

## Summary
Replace single `asset_update_options_enabled` feature flag with two
granular flags:
- `asset_deletion_enabled`: controls delete button visibility
- `asset_rename_enabled`: controls rename button visibility

The context menu only shows when at least one flag is enabled.

## Changes
- Updated `ServerFeatureFlag` enum with new flag names
- Updated `RemoteConfig` type with new properties
- Updated `AssetCard.vue` to conditionally show rename/delete buttons
based on their respective flags

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7864-feat-split-asset_update_options_enabled-into-separate-deletion-and-rename-flags-2e06d73d365081f9ac0afa12b87bd988)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>

src/composables/useFeatureFlags.ts

@@ -11,7 +11,8 @@ export enum ServerFeatureFlag {
   MAX_UPLOAD_SIZE = 'max_upload_size',
   MANAGER_SUPPORTS_V4 = 'extension.manager.supports_v4',
   MODEL_UPLOAD_BUTTON_ENABLED = 'model_upload_button_enabled',
-  ASSET_UPDATE_OPTIONS_ENABLED = 'asset_update_options_enabled',
+  ASSET_DELETION_ENABLED = 'asset_deletion_enabled',
+  ASSET_RENAME_ENABLED = 'asset_rename_enabled',
   PRIVATE_MODELS_ENABLED = 'private_models_enabled',
   ONBOARDING_SURVEY_ENABLED = 'onboarding_survey_enabled',
   HUGGINGFACE_MODEL_IMPORT_ENABLED = 'huggingface_model_import_enabled',
@@ -42,14 +43,16 @@ export function useFeatureFlags() {
         )
       )
     },
-    get assetUpdateOptionsEnabled() {
-      // Check remote config first (from /api/features), fall back to websocket feature flags
+    get assetDeletionEnabled() {
       return (
-        remoteConfig.value.asset_update_options_enabled ??
-        api.getServerFeature(
-          ServerFeatureFlag.ASSET_UPDATE_OPTIONS_ENABLED,
-          false
-        )
+        remoteConfig.value.asset_deletion_enabled ??
+        api.getServerFeature(ServerFeatureFlag.ASSET_DELETION_ENABLED, false)
+      )
+    },
+    get assetRenameEnabled() {
+      return (
+        remoteConfig.value.asset_rename_enabled ??
+        api.getServerFeature(ServerFeatureFlag.ASSET_RENAME_ENABLED, false)
       )
     },
     get privateModelsEnabled() {