Community analytics: track message volume & active members

[SaharPak]

Context

We want to understand community health — who's active, when peak hours are, and how engagement trends over time.

Requirements

• Track daily message count per chat
• Track unique active members per day/week
• Store in Supabase (depends on Add Supabase database for member tracking & moderation logs #1)
• /stats command shows: members today, messages today, top 5 active members this week

Metrics to track

• Messages per day/week/month
• Unique active members per day/week
• New members joined per day
• Members who left/were banned per day
• Peak activity hours

Acceptance Criteria

• Metrics stored in DB daily
• /stats command returns real data
• Data can be exported (JSON or CSV) for further analysis