Weekly community digest: auto-generate and post summary

[SaharPak]

Context

A weekly digest posted to the channel keeps members engaged and highlights what they missed.

Requirements

• Scheduled job (every Sunday or Monday)
• Auto-generate summary from the week's analytics:
  • New members count
  • Most discussed topics
  • Helpful messages/threads
  • Upcoming events (if tracked)
• Post formatted message to the Telegram channel
• Optionally also post to the group

Acceptance Criteria

• Digest auto-posts weekly without manual intervention
• Content is AI-generated from real group data
• Format is clean, readable, and engaging
• Can be disabled/enabled via config