Refactor processing logic and enhance error handling

- Cleaned up code in processing.py by removing inline semicolons and improving readability.
- Updated upsert_file_relation calls to ensure consistent handling of file relations.
- Enhanced query_file_relations in db_schema.py to support filtering by file existence.
- Improved API error handling in index.ts with user-friendly messages for 401 and 403 errors.
- Added online/offline status tracking in Layout.vue.
- Implemented debounced search functionality across multiple views to optimize performance.
- Introduced loading skeletons in Dashboard.vue for better user experience during data fetching.
- Enhanced file preview cleanup logic in Images.vue, Orders.vue, and Tables.vue to prevent memory leaks.
- Updated global styles to include new loading and notification animations.

web/frontend/src/views/Sync.vue

@@ -98,7 +98,10 @@ const processingStore = useProcessingStore()
 const syncing = ref(false)
 const syncStatus = ref({ enabled: false, repo_url: '' })
 
-const currentTask = computed(() => processingStore.currentTask)
+const currentTask = computed(() => {
+  if (processingStore.taskSource === 'sync') return processingStore.currentTask
+  return null
+})
 const logs = computed(() => processingStore.logs)
 
 const statusType = computed(() => {
@@ -240,7 +243,7 @@ onMounted(checkStatus)
 
 .sync-btn:hover:not(:disabled) {
   border-color: var(--amber-400);
-  box-shadow: 0 0 0 3px rgba(255,193,7,0.08);
+  box-shadow: 0 0 0 3px rgba(251,191,36,0.08);
   transform: translateY(-1px);
 }
 
@@ -312,7 +315,7 @@ onMounted(checkStatus)
 
 .progress-bar-fill {
   height: 100%;
-  background: linear-gradient(90deg, var(--amber-400), var(--amber-600));
+  background: linear-gradient(90deg, var(--amber-400), var(--amber-600, #d97706));
   border-radius: 3px;
   transition: width 0.4s var(--ease-out);
 }