Prepare QF100 pilot and Debian app deploy

src/shared/db/pool.ts

@@ -159,6 +159,7 @@ CREATE TABLE IF NOT EXISTS devices (
   updated_at TIMESTAMPTZ NOT NULL
 );
 CREATE INDEX IF NOT EXISTS idx_devices_status_last_seen ON devices (status, last_seen_at DESC);
+CREATE INDEX IF NOT EXISTS idx_devices_serial_number ON devices (serial_number);
 ALTER TABLE devices ADD COLUMN IF NOT EXISTS mqtt_username TEXT;
 ALTER TABLE devices ADD COLUMN IF NOT EXISTS credential_secret_fingerprint TEXT;
 ALTER TABLE devices ADD COLUMN IF NOT EXISTS credential_status TEXT NOT NULL DEFAULT 'not_issued';