automod and migrations

[Cufee]

Automod Feature

• New automod_verified field on users to track verification status
• Automod handler that deletes messages from unverified users and sends a temporary explainer with help image
• Automatic verification status updates when users interact with bot commands
• Users are auto-verified if they have existing connections, subscriptions, restrictions, or content

Migration Consolidation

• Replaced 5 incremental Atlas migrations with a single golang-migrate format migration (up/down)
• Cleaned up duplicate generated model/table files (removed plural-named duplicates)
• Switched migration format from Atlas native to golang-migrate for better tooling compatibility