Fix duplicate Escape hint in inspect-commit view

[dcavalcante]

Summary

• show Close [Esc] only while commit details are focused
• show Back [Esc] only while the diff is focused
• keep the Escape action first in the quick bar for both focus states

Cause

The inspect-commit popup registered Close [Esc] unconditionally and again while the diff was focused, so the quick bar showed the same action twice. Escape has different behavior in each focus state: it closes the popup from commit details and returns to commit details from the diff.

Testing

• cargo fmt --check
• cargo test