CREATE TABLE conversation_turns (
id TEXT PRIMARY KEY,
thread_id TEXT NOT NULL,
role TEXT NOT NULL,
text TEXT NOT NULL,
normalized_text TEXT,
source TEXT NOT NULL DEFAULT 'unknown',
source_event_id TEXT,
source_kind TEXT,
message_id TEXT,
turn_ts TEXT,
meta TEXT,
created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ','now')),
updated_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ','now')),
FOREIGN KEY (source_event_id) REFERENCES events(id) ON DELETE SET NULL DEFERRABLE INITIALLY DEFERRED
)