CREATE TABLE threads (
    id INTEGER PRIMARY KEY,
    thread_id TEXT NOT NULL UNIQUE,
    chat_id TEXT NOT NULL,
    title TEXT NOT NULL,
    summary TEXT NOT NULL DEFAULT '',
    status TEXT NOT NULL DEFAULT 'open',
    opened_at TEXT NOT NULL DEFAULT (datetime('now')),
    closed_at TEXT,
    last_referenced_scene_id INTEGER,
    created_at TEXT NOT NULL DEFAULT (datetime('now')),
    updated_at TEXT NOT NULL DEFAULT (datetime('now'))
);
CREATE INDEX threads_chat_status_idx ON threads(chat_id, status);