feat: refactor dual-track architecture (Phase 1-5)

## Backend Changes
- **Service Layer Refactoring**:
  - Add ProcessingOrchestrator for unified document processing
  - Add PDFTableRenderer for table rendering extraction
  - Add PDFFontManager for font management with CJK support
  - Add MemoryPolicyEngine (73% code reduction from MemoryGuard)

- **Bug Fixes**:
  - Fix Direct Track table row span calculation
  - Fix OCR Track image path handling
  - Add cell_boxes coordinate validation
  - Filter out small decorative images
  - Add covering image detection

## Frontend Changes
- **State Management**:
  - Add TaskStore for centralized task state management
  - Add localStorage persistence for recent tasks
  - Add processing state tracking

- **Type Consolidation**:
  - Merge shared types from api.ts to apiV2.ts
  - Update imports in authStore, uploadStore, ResultsTable, SettingsPage

- **Page Integration**:
  - Integrate TaskStore in ProcessingPage and TaskDetailPage
  - Update useTaskValidation hook with cache sync

## Testing
- Direct Track: edit.pdf (3 pages, 1.281s), edit3.pdf (2 pages, 0.203s)
- Cell boxes validation: 43 valid, 0 invalid
- Table merging: 12 merged cells verified

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/pages/ProcessingPage.tsx

@@ -16,6 +16,7 @@ import TableDetectionSelector from '@/components/TableDetectionSelector'
 import ProcessingTrackSelector from '@/components/ProcessingTrackSelector'
 import TaskNotFound from '@/components/TaskNotFound'
 import { useTaskValidation } from '@/hooks/useTaskValidation'
+import { useTaskStore, useProcessingState } from '@/store/taskStore'
 import type { LayoutModel, ProcessingOptions, PreprocessingMode, PreprocessingConfig, TableDetectionConfig, ProcessingTrack } from '@/types/apiV2'
 
 export default function ProcessingPage() {
@@ -23,6 +24,10 @@ export default function ProcessingPage() {
   const navigate = useNavigate()
   const { toast } = useToast()
 
+  // Use TaskStore for processing state management
+  const { startProcessing, stopProcessing, updateTaskStatus } = useTaskStore()
+  const processingState = useProcessingState()
+
   // Use shared hook for task validation
   const { taskId, taskDetail, isLoading: isValidating, isNotFound, clearAndReset } = useTaskValidation({
     refetchInterval: (query) => {
@@ -93,9 +98,16 @@ export default function ProcessingPage() {
         table_detection: tableDetectionConfig,
       }
 
+      // Update TaskStore processing state
+      startProcessing(forceTrack, options)
+
       return apiClientV2.startTask(taskId!, options)
     },
     onSuccess: () => {
+      // Update task status in cache
+      if (taskId) {
+        updateTaskStatus(taskId, 'processing', forceTrack || undefined)
+      }
       toast({
         title: '開始處理',
         description: 'OCR 處理已開始',
@@ -103,6 +115,8 @@ export default function ProcessingPage() {
       })
     },
     onError: (error: any) => {
+      // Stop processing state on error
+      stopProcessing()
       toast({
         title: t('errors.processingFailed'),
         description: error.response?.data?.detail || t('errors.networkError'),
@@ -111,14 +125,25 @@ export default function ProcessingPage() {
     },
   })
 
-  // Auto-redirect when completed
+  // Handle task status changes - update store and redirect when completed
   useEffect(() => {
     if (taskDetail?.status === 'completed') {
+      // Stop processing state and update cache
+      stopProcessing()
+      if (taskId) {
+        updateTaskStatus(taskId, 'completed', taskDetail.processing_track)
+      }
       setTimeout(() => {
         navigate('/tasks')
       }, 1000)
+    } else if (taskDetail?.status === 'failed') {
+      // Stop processing state on failure
+      stopProcessing()
+      if (taskId) {
+        updateTaskStatus(taskId, 'failed')
+      }
     }
-  }, [taskDetail?.status, navigate])
+  }, [taskDetail?.status, taskDetail?.processing_track, taskId, navigate, stopProcessing, updateTaskStatus])
 
   const handleStartProcessing = () => {
     processOCRMutation.mutate()