[Feature] Build a real-time collaborative pool chat/comments feature per group

[senmalong]

Closes #90

Overview

This PR implements a real-time collaborative group chat / discussion feature per savings pool, enabling group members to communicate, coordinate deposit timings, and build trust securely within the app.

Key Achievements

1. Database Schema & Row Level Security (RLS):

   • Created the pool_messages table with an optimized index for quick fetching.
   • Enforced Row Level Security (RLS) policies allowing select and insert access only to active members of the pool (matched against the pool_members table).
   • Constrained messages to <= 1000 characters using a PostgreSQL CHECK constraint.
   • Enforced rate-limiting (max 1 message per 3 seconds per sender) via a database trigger and function to guarantee server-side prevention of channel spamming.

2. Automated Notification Integration:

   • Implemented an AFTER INSERT trigger on the pool_messages table that automatically adds in-app notifications to the notifications table for all other pool members whenever a new message is posted.

3. Frontend Supabase Setup:

   • Registered the pool_messages table under TypeScript Database schema types.
   • Created getSupabaseClient(walletAddress) to dynamically instantiate Supabase clients with client-injected wallet headers to authorize RLS queries.

4. Sleek Discussion UI:

   • Integrated a beautiful, mobile-responsive Discussion tab alongside the Activity Log.
   • Leveraged Supabase Channels (postgres_changes events) to sync and display messages in real-time.
   • Included a local visual rate-limiting countdown and character counters.
   • Handled access restrictions gracefully by presenting clear user-friendly notices for non-members.

5. E2E Testing:

   • Added E2E specifications covering message submission, real-time message sync, client-side rate limit UI lockout, and RLS error access restriction state.

[Sendi0011]

@senmalong kindly resolve conflict please