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/schemas/receipt.py

@@ -6,7 +6,7 @@ from decimal import Decimal
 from typing import Optional, List, Any, Union
 from pydantic import BaseModel, Field, ConfigDict, field_validator
 
-from backend.modules.data_entry.db.models.receipt import ReceiptType, ReceiptDirection, ReceiptStatus
+from backend.modules.data_entry.db.models.receipt import ReceiptType, ReceiptDirection, ReceiptStatus, ProcessingStatus
 from backend.modules.data_entry.db.models.accounting_entry import EntryType
 
 
@@ -161,6 +161,14 @@ class ReceiptResponse(ReceiptBase):
     oracle_act_id: Optional[int] = None
     oracle_error: Optional[str] = None
 
+    # Bulk upload batch tracking (US-012)
+    batch_id: Optional[str] = None
+    processing_status: Optional[str] = None
+    processing_error: Optional[str] = None
+    file_hash: Optional[str] = None
+    processing_started_at: Optional[datetime] = None
+    processing_completed_at: Optional[datetime] = None
+
     # Relationships (optional, loaded when needed)
     attachments: List[AttachmentResponse] = []
     entries: List[AccountingEntryResponse] = []
@@ -196,6 +204,14 @@ class ReceiptResponse(ReceiptBase):
         return None
 
 
+class ProcessingStats(BaseModel):
+    """Statistics for bulk upload processing status (US-012)."""
+    pending_count: int = 0
+    processing_count: int = 0
+    completed_count: int = 0
+    failed_count: int = 0
+
+
 class ReceiptListResponse(BaseModel):
     """Schema for paginated receipt list response."""
     items: List[ReceiptResponse]
@@ -203,6 +219,8 @@ class ReceiptListResponse(BaseModel):
     page: int
     page_size: int
     pages: int
+    # Processing stats for bulk upload filtering (US-012)
+    processing_stats: Optional[ProcessingStats] = None
 
 
 class ReceiptFilter(BaseModel):
@@ -214,6 +232,11 @@ class ReceiptFilter(BaseModel):
     date_from: Optional[date] = None
     date_to: Optional[date] = None
     search: Optional[str] = None  # Search in description, partner_name
+    # Bulk upload filters (US-012)
+    processing_status: Optional[str] = None  # ProcessingStatus enum value
+    batch_id: Optional[str] = None  # Filter by batch_id
+    sort_by: Optional[str] = None  # Sort field (e.g., "processing_started_at")
+    # Pagination
     page: int = Field(default=1, ge=1)
     page_size: int = Field(default=20, ge=1, le=100)
 
@@ -267,3 +290,22 @@ class ExpenseTypeOption(BaseModel):
     account_code: str
     has_vat: bool
     vat_percent: Decimal = Decimal("19")
+
+
+# ============ Bulk Delete Schemas (US-024) ============
+
+class BulkDeleteRequest(BaseModel):
+    """Request schema for bulk delete endpoint."""
+    ids: List[int] = Field(..., min_length=1, description="List of receipt IDs to delete")
+
+
+class BulkDeleteFailure(BaseModel):
+    """Schema for a single failed deletion."""
+    id: int
+    error: str
+
+
+class BulkDeleteResponse(BaseModel):
+    """Response schema for bulk delete with partial success support."""
+    deleted: List[int] = Field(default_factory=list, description="IDs of successfully deleted receipts")
+    failed: List[BulkDeleteFailure] = Field(default_factory=list, description="IDs that failed with error messages")