feat: Add multiple TVA entries support for Romanian receipts

- Add TvaEntry schema supporting multiple TVA rates (A, B, C, D codes)
- Update OCR extractor to extract multiple TVA entries from receipts
- Support both old (19%, 9%, 5%) and new Romanian rates (21%, 11% from Aug 2025)
- Add tva_breakdown, tva_total, items_count, vendor_address to Receipt model
- Update OCRPreview.vue to display TVA entries with rate badges
- Add "Detalii Suplimentare" section in ReceiptCreateView with editable TVA table
- Add TVA breakdown display in ReceiptDetailView
- Create database migration for new TVA columns

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

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

data-entry-app/backend/app/services/ocr_engine.py

@@ -64,11 +64,17 @@ class OCREngine:
                 PaddleOCR = _PaddleOCR
 
                 print("Initializing PaddleOCR engine...")
-                # PaddleOCR 3.x API - simplified parameters
+                # PaddleOCR 3.x API - optimized for Romanian receipts
                 self._paddle = PaddleOCR(
-                    lang='en',  # Better for mixed text with numbers
+                    lang='en',  # 'en' works better than 'ro' for mixed alphanumeric
+                    # High quality settings for better accuracy
+                    det_db_thresh=0.3,      # Lower threshold = detect more text (default 0.3)
+                    det_db_box_thresh=0.5,  # Box confidence threshold (default 0.5)
+                    det_db_unclip_ratio=1.8,  # Expand detected boxes slightly (default 1.5)
+                    rec_batch_num=6,        # Batch size for recognition
+                    use_angle_cls=True,     # Enable text angle classification
                 )
-                print("PaddleOCR initialized successfully")
+                print("PaddleOCR initialized successfully with high-quality settings")
             except Exception as e:
                 print(f"Warning: Failed to initialize PaddleOCR: {e}")
                 self._paddle = None