Migrate the user-facing strings in builtin.git (panel, status groups, commit bar, branch picker, discard dialog, row a11y) and builtin.diff (toolbar, empty states, file meta) to ClideSettings.i18n.string/.interpolated; extend both catalogs. _stateLabel threaded a BuildContext from its caller. No en_US behaviour change (D-21). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>