- flowpilot_engine: pass account_id at all 5 AISessionStep instantiation
sites (_create_step_from_parsed x3, briefing step, status update step).
Phase 4 RLS blocked every INSERT with NULL account_id — this broke all
new FlowPilot sessions since the Phase 4 migration was applied.
- integrations: list_boards returns [] on PSAError instead of 502, stopping
the spurious 'Server error' toast on dashboard load (boards are optional).
- client.ts: 5xx global toast now shows backend detail when available.
- useFlowPilotSession: startSession extracts backend detail for error state;
suppresses duplicate toast for 5xx (global interceptor already handles it).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>