feat(data-entry): Bulk Receipt Upload cu Mobile UX Android Nativ

## Funcționalități Principale

### Bulk Upload & Processing
- Drag & drop pentru upload bonuri multiple oriunde pe pagină
- Batch processing cu job queue și worker pool
- Real-time updates via SSE (Server-Sent Events) cu fallback polling
- Duplicate detection via SHA-256 file hash
- Auto-retry pentru job-uri failed
- Cancel individual jobs sau batch complet

### Mobile UX - Android Native Style
- Top bar fixă cu hamburger, titlu centrat, acțiuni (search/filter)
- Bottom navigation cu 4 tab-uri (Bonuri, Upload, Rapoarte, Setări)
- FAB (Floating Action Button) cu hide/show on scroll
- Filter chips orizontal scrollabile
- Selecție multiplă prin long-press (500ms)
- Select All + Bulk Delete cu confirmare
- Layout Android pentru Create/Edit/View bon (Gmail compose style)

### Bug Fixes
- Refresh individual via SSE în loc de refresh total pagină
- Bonurile cu eroare OCR rămân vizibile pentru editare manuală
- Afișare nume fișier original pentru toate bonurile
- Upload stabil pe mobil (fix race condition File API)
- Păstrare ordine bonuri la refresh (nu se reordonează)

### Backend
- SSE endpoint pentru status updates real-time
- Bulk delete endpoint cu partial success
- Auto-cleanup bonuri failed după 7 zile
- Batch model cu tracking complet

### Testing
- E2E tests cu Playwright
- Unit tests pentru bulk upload, auto-create, cleanup

## Commits Squashed: 43 user stories (US-001 → US-043)
## Branch: ralph/bulk-receipt-upload
## Timp dezvoltare: ~3 zile (Ralph autonomous)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/modules/data_entry/db/crud/receipt.py

@@ -147,13 +147,33 @@ class ReceiptCRUD:
                 )
             )
 
+        # Bulk upload filters (US-012)
+        # US-005: Support comma-separated values for processing_status filter (e.g., "pending,processing")
+        if filters.processing_status:
+            statuses = [s.strip() for s in filters.processing_status.split(",")]
+            if len(statuses) == 1:
+                query = query.where(Receipt.processing_status == statuses[0])
+            else:
+                query = query.where(Receipt.processing_status.in_(statuses))
+
+        if filters.batch_id:
+            query = query.where(Receipt.batch_id == filters.batch_id)
+
         # Count total
         count_query = select(func.count()).select_from(query.subquery())
         total_result = await session.execute(count_query)
         total = total_result.scalar() or 0
 
-        # Apply pagination and ordering
-        query = query.order_by(Receipt.created_at.desc())
+        # Apply ordering based on sort_by parameter (US-012)
+        if filters.sort_by == "processing_started_at":
+            query = query.order_by(Receipt.processing_started_at.desc())
+        elif filters.sort_by == "processing_started_at_asc":
+            query = query.order_by(Receipt.processing_started_at.asc())
+        else:
+            # Default ordering
+            query = query.order_by(Receipt.created_at.desc())
+
+        # Apply pagination
         offset = (filters.page - 1) * filters.page_size
         query = query.offset(offset).limit(filters.page_size)
 
@@ -163,6 +183,61 @@ class ReceiptCRUD:
 
         return list(receipts), total
 
+    @staticmethod
+    async def get_processing_stats(
+        session: AsyncSession,
+        company_id: Optional[int] = None,
+        batch_id: Optional[str] = None,
+    ) -> dict:
+        """Get processing status counts for bulk uploaded receipts (US-012)."""
+        # Build base query for counting by processing_status
+        base_conditions = []
+
+        if company_id:
+            base_conditions.append(Receipt.company_id == company_id)
+
+        if batch_id:
+            base_conditions.append(Receipt.batch_id == batch_id)
+
+        # Only count receipts that have a processing_status (bulk uploads)
+        base_conditions.append(Receipt.processing_status.isnot(None))
+
+        query = select(
+            Receipt.processing_status,
+            func.count(Receipt.id).label("count")
+        )
+
+        for condition in base_conditions:
+            query = query.where(condition)
+
+        query = query.group_by(Receipt.processing_status)
+
+        result = await session.execute(query)
+        rows = result.all()
+
+        # Initialize stats
+        stats = {
+            "pending_count": 0,
+            "processing_count": 0,
+            "completed_count": 0,
+            "failed_count": 0,
+        }
+
+        # Map results
+        for row in rows:
+            status = row.processing_status
+            count = row.count
+            if status == "pending":
+                stats["pending_count"] = count
+            elif status == "processing":
+                stats["processing_count"] = count
+            elif status == "completed":
+                stats["completed_count"] = count
+            elif status == "failed":
+                stats["failed_count"] = count
+
+        return stats
+
     @staticmethod
     async def get_pending_review(
         session: AsyncSession,