feat: negotiate room event plans over WeChat

[Ltcc0]

Summary

• create a versioned event-plan draft when the initial pair accepts and pause room expansion until both founders confirm the same version
• let founders update/confirm time, place, and catalog games through natural-language agent actions and dedicated room APIs
• proactively deliver the plan through the canonical WeChat outbound ledger, with stable client IDs and up to 8 retry attempts
• include the published plan in room-join invites, accepted-room notifications, current-member broadcasts, and pending-invite updates
• keep capacity governed by the published primary game's max-player limit

Database and security

• adds room_event_plans, room_event_plan_games, room_event_plan_confirmations, founder roles, atomic proactive message RPCs, and expansion gates
• reuses channel_message_deliveries rather than introducing a second outbound queue
• enables RLS on new tables, revokes public/anon/authenticated access, and grants service-role-only RPC access
• backfills completed rooms with published plans and incomplete rooms with gated drafts

Validation

• pnpm check
• pnpm agent:migrations:check
• PGlite migration suite: 24/24 passed

Production rollout

After merge: apply migration 20260726020000_event_plan_and_wechat_outbox.sql, then redeploy API, intelligence worker, and WeChat iLink worker and run production health/smoke checks.