When tablet_session_mode='session_swap', the server attributes every write via request.env.user — there's no need to pass tablet_tech_id in the RPC params. Caches the mode lookup at module level so we don't round-trip on every RPC. Legacy mode unchanged — fpRpc still injects tablet_tech_id from techStore.currentTechId. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>