Serve recent stages from SQLite with configurable background refresh

backend/app/db.py

@@ -187,6 +187,7 @@ def _has_secure_bootstrap_admin_credentials() -> bool:
 
 def init_db() -> None:
     with _connect() as conn:
+        conn.execute("CREATE TABLE IF NOT EXISTS request_stage_cache (request_id INTEGER PRIMARY KEY, source_updated TEXT, ready INTEGER NOT NULL, checked_at REAL NOT NULL)")
         conn.execute("""CREATE TABLE IF NOT EXISTS user_duplicate_repairs (
             id INTEGER PRIMARY KEY AUTOINCREMENT, kept_user_id INTEGER NOT NULL,
             archive_json TEXT NOT NULL, repaired_by TEXT NOT NULL, repaired_at TEXT NOT NULL)""")
@@ -855,6 +856,7 @@ def save_action(
 ) -> None:
     created_at = datetime.now(timezone.utc).isoformat()
     with _connect() as conn:
+        conn.execute('UPDATE request_stage_cache SET checked_at = 0 WHERE request_id = ?', (request_id,))
         conn.execute(
             """
             INSERT INTO actions (request_id, action_id, label, status, message, created_at)
@@ -2879,7 +2881,7 @@ def get_cached_requests_since(since_iso: str) -> list[Dict[str, Any]]:
         rows = conn.execute(
             """
             SELECT request_id, media_id, media_type, status, title, year, requested_by,
-                   requested_by_norm, requested_by_id, created_at
+                   requested_by_norm, requested_by_id, created_at, updated_at
             FROM requests_cache
             WHERE created_at >= ?
             ORDER BY created_at DESC, request_id DESC
@@ -2900,6 +2902,7 @@ def get_cached_requests_since(since_iso: str) -> list[Dict[str, Any]]:
                 "requested_by_norm": row[7],
                 "requested_by_id": row[8],
                 "created_at": row[9],
+                "updated_at": row[10],
             }
         )
     return results
@@ -4027,3 +4030,15 @@ def cleanup_history(days: int) -> Dict[str, int]:
             (cutoff,),
         ).rowcount
     return {"actions": actions, "snapshots": snapshots}
+
+
+def get_request_stage_cache():
+    with _connect() as conn:
+        return {row[0]: {'source_updated': row[1], 'ready': bool(row[2]), 'checked_at': row[3]}
+                for row in conn.execute('SELECT request_id, source_updated, ready, checked_at FROM request_stage_cache')}
+
+
+def save_request_stage_cache(rows):
+    with _connect() as conn:
+        conn.executemany('INSERT OR REPLACE INTO request_stage_cache (request_id, source_updated, ready, checked_at) VALUES (?, ?, ?, ?)', rows)
+        conn.execute('DELETE FROM request_stage_cache WHERE request_id NOT IN (SELECT request_id FROM requests_cache)')