feat(server): add attachment ORM models and table provisioning

Adds 5 tables in the CargoTrace schema: attachment_category,
finished_goods_attachment, finished_goods_attachment_item,
finished_goods_attachment_location, finished_goods_box_attachment_item.
Includes a one-off create_all script and extends test cleanup.

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

tests/conftest.py

@@ -34,7 +34,36 @@ def cleanup_test_data(db: Session):
         "26T998",
         "26B998",
         "26C998",
+        "26BW0011",
+        "26BW0012",
     ]
+
+    # Attachment tables (order: children before parents / before shared box)
+    from app.models.attachment import (
+        AttachmentCategory,
+        FinishedGoodsAttachment,
+        FinishedGoodsAttachmentItem,
+        FinishedGoodsAttachmentLocation,
+        FinishedGoodsBoxAttachmentItem,
+    )
+
+    db.query(FinishedGoodsBoxAttachmentItem).filter(
+        FinishedGoodsBoxAttachmentItem.zongpai_no.in_(test_zongpai_nos)
+    ).delete(synchronize_session=False)
+    db.query(FinishedGoodsAttachmentLocation).filter(
+        FinishedGoodsAttachmentLocation.zongpai_no.in_(test_zongpai_nos)
+    ).delete(synchronize_session=False)
+    db.query(FinishedGoodsAttachmentItem).filter(
+        FinishedGoodsAttachmentItem.zongpai_no.in_(test_zongpai_nos)
+    ).delete(synchronize_session=False)
+    db.query(FinishedGoodsAttachment).filter(
+        FinishedGoodsAttachment.zongpai_no.in_(test_zongpai_nos)
+    ).delete(synchronize_session=False)
+    db.query(AttachmentCategory).filter(
+        AttachmentCategory.name.like("TEST_%")
+    ).delete(synchronize_session=False)
+
+    # Existing product cleanup (unchanged) — attachment box items for these boxes:
     db.query(FinishedGoodsLocation).filter(
         FinishedGoodsLocation.zongpai_no.in_(test_zongpai_nos)
     ).delete(synchronize_session=False)
@@ -48,6 +77,9 @@ def cleanup_test_data(db: Session):
     )
     test_box_ids = [box.id for box in test_boxes]
     if test_box_ids:
+        db.query(FinishedGoodsBoxAttachmentItem).filter(
+            FinishedGoodsBoxAttachmentItem.box_id.in_(test_box_ids)
+        ).delete(synchronize_session=False)
         db.query(FinishedGoodsBoxItem).filter(
             FinishedGoodsBoxItem.box_id.in_(test_box_ids)
         ).delete(synchronize_session=False)