Implement comprehensive connection caching system to prevent XMPP connection leaks and support HA environments:
- Add node-specific XMPP resources using format "{baseResource}-node-{diagnosticId[:8]}" for HA compatibility
- Implement thread-safe connection cache with mutex protection in UserManager
- Add cache-first lookup in GetUser/GetOrCreateUser methods to prevent duplicate connections
- Update lifecycle manager to efficiently check cached users instead of expensive KV store queries
- Add graceful shutdown cleanup to properly disconnect all cached connections
- Implement cache management methods: getCachedUser, cacheUser, removeCachedUser, getCachedUsers
- Update activity tracking to work with cached connections
- Add proper cache cleanup when users are disconnected or deleted
This prevents connection leaks identified in previous implementation while maintaining efficient ghost user lifecycle management with 30-minute inactivity timeout.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
- Extract bridge user detection logic into separate isBridgeUserMessage() function
- Fix gocritic ifElseChain issues by converting if-else to switch statements
- Fix gofmt formatting issues in client.go
- Fix revive naming issues by renaming XMPPUser to User and XMPPUserManager to UserManager
- Improve code organization and maintainability
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
