[FEATURE] Add Supabase memory backend for persistent agent memory

[Ablaze005]

Feature Request: Supabase Memory Backend

Aider currently stores memory locally, but many users want cloud-based persistent memory.

Why Supabase?

• Simple REST + Python client
• Free tier suitable for open-source users
• Works well with agentic workflows

Proposed Implementation

• Add a memory backend using Supabase tables.
• Provide config options for URL and API key.
• Support read/write operations for conversation memory.

I can contribute the initial implementation.