fix(loyalty): align /locations endpoint shape with template bindings

The shared loyalty list partials (pins, cards, transactions, devices,
admin merchant detail) bind store filter dropdowns to
loc.store_id/loc.store_name, but the /merchants/loyalty/locations and
/admin/loyalty/merchants/{id}/locations endpoints were returning
{id, name, code}. Result: every store-filter dropdown was silently
empty across the loyalty module.

Switch both endpoints to {store_id, store_name, store_code}, matching
the shape used everywhere else (analytics, location stats). Storefront
locations come from a different code path and are unaffected.

Drop the temporary normalizer in the devices Alpine factory now that
the endpoint speaks the right shape.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/modules/loyalty/routes/api/merchant.py

@@ -530,9 +530,17 @@ def list_locations(
     merchant: Merchant = Depends(get_merchant_for_current_user),
     db: Session = Depends(get_db),
 ):
-    """List merchant stores (for filter dropdowns)."""
+    """List merchant stores (for filter dropdowns).
+
+    Shape matches what the shared loyalty list partials bind to
+    (`loc.store_id` / `loc.store_name` / `loc.store_code`).
+    """
     locations = program_service.get_merchant_locations(db, merchant.id)
     return [
-        {"id": loc.id, "name": loc.name, "code": loc.store_code}
+        {
+            "store_id": loc.id,
+            "store_name": loc.name,
+            "store_code": loc.store_code,
+        }
         for loc in locations
     ]