fix alembic migration files

api/alembic/versions/0005_cleanup_cross_chapter_story_links.py

@@ -9,6 +9,7 @@ Revises: 0004_memory_embedding_1024
 from typing import Sequence, Union
 
 import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
 
 from alembic import op
 
@@ -18,7 +19,42 @@ branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
 
 
+def _has_column(table: str, column: str) -> bool:
+    bind = op.get_bind()
+    return any(c["name"] == column for c in sa.inspect(bind).get_columns(table))
+
+
+def _ensure_chapter_materialization_columns() -> None:
+    """Keep older/squashed staging schemas compatible before this data cleanup."""
+    if not _has_column("chapters", "markdown_compose_dirty"):
+        op.add_column(
+            "chapters",
+            sa.Column(
+                "markdown_compose_dirty",
+                sa.Boolean(),
+                nullable=False,
+                server_default=sa.text("false"),
+            ),
+        )
+    if not _has_column("chapters", "markdown_composed_at"):
+        op.add_column(
+            "chapters",
+            sa.Column("markdown_composed_at", sa.DateTime(timezone=True), nullable=True),
+        )
+    if not _has_column("chapters", "reading_segments_json"):
+        op.add_column(
+            "chapters",
+            sa.Column(
+                "reading_segments_json",
+                postgresql.JSON(astext_type=sa.Text()),
+                nullable=True,
+            ),
+        )
+
+
 def upgrade() -> None:
+    _ensure_chapter_materialization_columns()
+
     # 先标脏，再删链接（子查询在 DELETE 后不可用）
     op.execute(
         sa.text(