chore: import upstream snapshot with attribution

migrations/V010__transcript_turn_usage.py

@@ -0,0 +1,60 @@
+"""V010 - persist per-turn usage metadata on transcript entries."""
+
+from __future__ import annotations
+
+from yoyo import step
+
+__depends__: set[str] = {"V009__transcript_reasoning_content"}
+
+TABLE = "transcript_entries"
+COLUMN = "turn_usage"
+ADD_COLUMN_DDL = f"ALTER TABLE {TABLE} ADD COLUMN {COLUMN} TEXT"
+DROP_COLUMN_DDL = f"ALTER TABLE {TABLE} DROP COLUMN {COLUMN}"
+
+
+def _table_exists(conn, table: str) -> bool:
+    cur = conn.cursor()
+    cur.execute(
+        "SELECT 1 FROM sqlite_master WHERE type='table' AND name=?",
+        (table,),
+    )
+    return cur.fetchone() is not None
+
+
+def _has_column(conn, table: str, column: str) -> bool:
+    cur = conn.cursor()
+    cur.execute(f"PRAGMA table_info({table})")
+    return any(row[1] == column for row in cur.fetchall())
+
+
+def _sqlite_version(conn) -> tuple[int, int, int]:
+    cur = conn.cursor()
+    cur.execute("SELECT sqlite_version()")
+    raw = cur.fetchone()[0]
+    parts = raw.split(".")
+    while len(parts) < 3:
+        parts.append("0")
+    return (int(parts[0]), int(parts[1]), int(parts[2]))
+
+
+def apply_step(conn) -> None:
+    if not _table_exists(conn, TABLE):
+        return
+    if _has_column(conn, TABLE, COLUMN):
+        return
+    cur = conn.cursor()
+    cur.execute(ADD_COLUMN_DDL)
+
+
+def rollback_step(conn) -> None:
+    if not _table_exists(conn, TABLE):
+        return
+    if not _has_column(conn, TABLE, COLUMN):
+        return
+    if _sqlite_version(conn) < (3, 35, 0):
+        return
+    cur = conn.cursor()
+    cur.execute(DROP_COLUMN_DDL)
+
+
+steps = [step(apply_step, rollback_step)]