feat: 导入 MemRelay 初始源码

backend/migrations/versions/20260804_0008_curated_metadata.py

@@ -0,0 +1,29 @@
+"""Persist curated document metadata for every revision."""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "20260804_0008"
+down_revision: str | Sequence[str] | None = "20260804_0007"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    with op.batch_alter_table("curated_documents") as batch:
+        batch.add_column(
+            sa.Column("metadata_json", sa.Text(), nullable=False, server_default="{}")
+        )
+    with op.batch_alter_table("curated_document_revisions") as batch:
+        batch.add_column(
+            sa.Column("metadata_json", sa.Text(), nullable=False, server_default="{}")
+        )
+
+
+def downgrade() -> None:
+    with op.batch_alter_table("curated_document_revisions") as batch:
+        batch.drop_column("metadata_json")
+    with op.batch_alter_table("curated_documents") as batch:
+        batch.drop_column("metadata_json")