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/test_attachment_models_smoke.py

@@ -0,0 +1,22 @@
+from sqlalchemy.orm import Session
+
+from app.models.attachment import AttachmentCategory, FinishedGoodsAttachment
+
+
+def test_category_round_trip(db: Session):
+    cat = AttachmentCategory(name="TEST_SMOKE", sort_order=1, is_active=True)
+    db.add(cat)
+    db.commit()
+    db.refresh(cat)
+    assert cat.id is not None
+    fetched = db.query(AttachmentCategory).filter_by(name="TEST_SMOKE").first()
+    assert fetched is not None
+    assert fetched.is_active is True
+
+
+def test_attachment_defaults_to_undetermined(db: Session):
+    att = FinishedGoodsAttachment(zongpai_no="26BW0011")
+    db.add(att)
+    db.commit()
+    db.refresh(att)
+    assert att.determination == "undetermined"