Debug Supabase Realtime PostgREST Filter Join Timeout

Problem: Realtime subscription crashes during high-concurrency multi-tenant updates.Root Cause: A complex PostgreSQL trigger combined with recursive Row-Level Security (RLS) policies is causing an infinite recursion or timeout loop under load. Task: Optimize the nested SQL security definer function and refactor the TypeScript client filter logic to use proper channel broadcasting instead of heavy database polling. Deliverable: Optimized SQL policy script and patched TypeScript subscription code that passes stress testing under 100 concurrent writes.