Fix(TUI): Reliably Update Branch Tooltip on Git Checkout

[spoons-and-mirrors]

Issue

The git branch status is not updating reliably (if at all) once the app has started)

Summary

• Fixes TUI branch tooltip to update immediately after git branch changes
• Watches the entire .git directory for Write/Create/Rename events, ensuring atomic HEAD/ref updates
  are detected across platforms.
• Removes previous debounce logic that caused stale branch display.
• Adds a short delay and drains event bursts before reading the branch, eliminating the "one behind"
  lag.