When the app regains focus, checks git diff for renames (--diff-filter=R).
If renamed .md files are found, shows a non-blocking banner with "Update
wikilinks" and "Ignore" buttons. The update reuses the existing vault-wide
wikilink replacement logic from rename.rs.
New Tauri commands: detect_renames, update_wikilinks_for_renames.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
