[Enhance] When activating "Search Commits", focus the search box to start typing directly

[goran-w]

It would be very useful if the "Search Commits" toggle button (Ctrl+Shift+F) would put keyboard focus into the search-text box directly when activated, so we can start typing a search phrase directly.

That would also position us better in tab-order sequence, for reaching adjacent UI items within the Search Commits panel.

Additionally, the Ctrl+Shift+F hotkey should be able to deactivate (untoggle) the Search Commits panel, not just activate it.