Fix frozen spinner during MCP tool loading

[dgageot]

When MCP tools take a bit of time to start, the TUI feels irresponsive because it starts showing a spinner next to the number of tools but the spinner is frozen in spinning state until the final number of tools is received.

Assisted-By: docker-agent

[docker-agent]

Review Summary

Assessment: 🟢 APPROVE

Summary

This PR successfully fixes the frozen spinner issue during MCP tool loading. The change is clean and follows good architectural patterns.

What Changed:

• Removed direct call to sidebar.SetToolsetInfo() from the chat page
• Now forwards the ToolsetInfoEvent to the sidebar via forwardToSidebar()
• The sidebar's Update() method handles the event and manages its own state

Why This Works:
The sidebar's Update() method already has a case handler for ToolsetInfoEvent (line 707 in sidebar.go) that calls SetToolsetInfo() with the same parameters. By forwarding the event instead of directly calling the method, the sidebar can now properly manage the spinner lifecycle internally through its event loop, preventing the frozen spinner issue.

Code Quality:

• ✅ No race conditions introduced
• ✅ Follows the Elm Architecture pattern used throughout the codebase
• ✅ Maintains separation of concerns (sidebar manages its own UI state)
• ✅ No breaking changes to the API
• ✅ Consistent with how other events are handled (e.g., SessionTitleEvent)

Findings

No bugs detected. The implementation is correct and improves the architecture.