feat(loyalty): multi-select categories on transactions

Switch from single category_id to category_ids JSON array on
transactions. Sellers can now select multiple categories (e.g.,
Men + Accessories) when entering stamp/points transactions.

- Migration loyalty_009: drop category_id FK, add category_ids JSON
- Schemas: category_id → category_ids (list[int] | None)
- Services: stamp_service + points_service accept category_ids
- Terminal UI: pills are now multi-select (toggle on/off)
- Transaction response: category_names (list[str]) resolved from IDs
- Recent transactions table: new Category column showing comma-
  separated names

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/modules/loyalty/services/card_service.py

@@ -836,8 +836,8 @@ class CardService:
                 "transaction_at": tx.transaction_at.isoformat() if tx.transaction_at else None,
                 "notes": tx.notes,
                 "store_name": None,
-                "category_id": tx.category_id,
-                "category_name": None,
+                "category_ids": tx.category_ids,
+                "category_names": None,
             }
 
             if tx.store_id:
@@ -845,15 +845,19 @@ class CardService:
                 if store_obj:
                     tx_data["store_name"] = store_obj.name
 
-            if tx.category_id:
+            if tx.category_ids and isinstance(tx.category_ids, list):
                 from app.modules.loyalty.services.category_service import (
                     category_service,
                 )
 
-                cat_name = category_service.validate_category_for_store(
-                    db, tx.category_id, tx.store_id or 0
-                )
-                tx_data["category_name"] = cat_name
+                names = []
+                for cid in tx.category_ids:
+                    name = category_service.validate_category_for_store(
+                        db, cid, tx.store_id or 0
+                    )
+                    if name:
+                        names.append(name)
+                tx_data["category_names"] = names if names else None
 
             tx_responses.append(tx_data)
 

app/modules/loyalty/services/points_service.py

@@ -49,7 +49,7 @@ class PointsService:
         purchase_amount_cents: int,
         order_reference: str | None = None,
         staff_pin: str | None = None,
-        category_id: int | None = None,
+        category_ids: list[int] | None = None,
         ip_address: str | None = None,
         user_agent: str | None = None,
         notes: str | None = None,
@@ -104,7 +104,7 @@ class PointsService:
             raise OrderReferenceRequiredException()
 
         # Category is mandatory when the store has categories configured
-        if not category_id:
+        if not category_ids:
             from app.modules.loyalty.services.category_service import category_service
 
             store_categories = category_service.list_categories(
@@ -196,7 +196,7 @@ class PointsService:
             card_id=card.id,
             store_id=store_id,
             staff_pin_id=verified_pin.id if verified_pin else None,
-            category_id=category_id,
+            category_ids=category_ids,
             transaction_type=TransactionType.POINTS_EARNED.value,
             points_delta=points_earned,
             stamps_balance_after=card.stamp_count,

app/modules/loyalty/services/stamp_service.py

@@ -46,7 +46,7 @@ class StampService:
         qr_code: str | None = None,
         card_number: str | None = None,
         staff_pin: str | None = None,
-        category_id: int | None = None,
+        category_ids: list[int] | None = None,
         ip_address: str | None = None,
         user_agent: str | None = None,
         notes: str | None = None,
@@ -144,7 +144,7 @@ class StampService:
             card_id=card.id,
             store_id=store_id,
             staff_pin_id=verified_pin.id if verified_pin else None,
-            category_id=category_id,
+            category_ids=category_ids,
             transaction_type=TransactionType.STAMP_EARNED.value,
             stamps_delta=1,
             stamps_balance_after=card.stamp_count,