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/Dashboard.vue

@@ -3,6 +3,19 @@
     <!-- Top stats row -->
     <div class="stats-row animate-in">
       <div
+        v-if="statsLoading"
+        v-for="n in 4"
+        :key="'sk'+n"
+        class="stat-card"
+      >
+        <div class="skeleton skeleton-circle" style="width:44px;height:44px;border-radius:12px"></div>
+        <div class="stat-info" style="gap:4px">
+          <div class="skeleton skeleton-text" style="width:48px;height:24px"></div>
+          <div class="skeleton skeleton-text short" style="width:64px;height:14px"></div>
+        </div>
+      </div>
+      <div
+        v-if="!statsLoading"
         class="stat-card"
         v-for="stat in stats"
         :key="stat.label"
@@ -183,6 +196,7 @@ const uploadingName = ref('')
 const processing = ref(false)
 const fileInput = ref<HTMLInputElement>()
 const logBox = ref<HTMLElement>()
+const statsLoading = ref(true)
 
 const detailedStats = ref({
   input_images: 0,
@@ -260,12 +274,6 @@ const stats = computed(() => [
   },
 ])
 
-function fmtSize(b: number): string {
-  if (b < 1024) return b + ' B'
-  if (b < 1048576) return (b / 1024).toFixed(1) + ' KB'
-  return (b / 1048576).toFixed(1) + ' MB'
-}
-
 function fmtTime(i: number): string {
   const d = new Date()
   d.setSeconds(d.getSeconds() - (logs.value.length - i))
@@ -283,11 +291,14 @@ function clearLogs(): void {
 }
 
 async function refreshStats(): Promise<void> {
+  statsLoading.value = true
   try {
     const res = await api.get('/files/stats/detailed')
     detailedStats.value = res.data
   } catch {
     // silent
+  } finally {
+    statsLoading.value = false
   }
 }
 
@@ -328,6 +339,7 @@ async function upload(files: File[]): Promise<void> {
   uploading.value = true
   uploadPct.value = 0
   const uploadedFiles: { name: string; type: string }[] = []
+  const failedFiles: string[] = []
   for (let i = 0; i < files.length; i++) {
     const file = files[i]
     uploadingName.value = file.name
@@ -344,9 +356,8 @@ async function upload(files: File[]): Promise<void> {
       })
       const typeLabel = getFileTypeLabel(file.name)
       uploadedFiles.push({ name: file.name, type: typeLabel })
-      ElMessage.success(`${file.name} → ${typeLabel === 'OCR' ? '全流程处理队列' : 'Excel处理队列'}`)
     } catch (err: any) {
-      ElMessage.error(`上传失败: ${file.name}`)
+      failedFiles.push(file.name)
     }
   }
   uploading.value = false
@@ -354,15 +365,21 @@ async function upload(files: File[]): Promise<void> {
   uploadPct.value = 0
   refreshStats()
 
+  // Show upload results
+  if (uploadedFiles.length > 0) {
+    ElMessage.success(`${uploadedFiles.length} 个文件上传成功`)
+  }
+  if (failedFiles.length > 0) {
+    ElMessage.error(`${failedFiles.length} 个文件上传失败: ${failedFiles.join(', ')}`)
+  }
+
   // Auto-process: pipeline for images, excel for Excel files
   if (uploadedFiles.length > 0) {
     const hasImages = uploadedFiles.some(f => f.type === 'OCR')
     const hasExcel = uploadedFiles.some(f => f.type === 'Excel')
     if (hasImages) {
-      ElMessage.info('自动启动一键全流程...')
       await doAction('/processing/pipeline')
     } else if (hasExcel) {
-      ElMessage.info('自动启动Excel处理...')
       await doAction('/processing/excel')
     }
   }