#22785 cmux-next settings: Undo bar clears the last row, titles and density names line up (layout pass 1)

Layout pass: running list

Defects from the layout pass (gallery, dark, 16x9) and where each goes. ✅ = this PR.

• ✅ Settings: Undo/Redo/Reset bar covered the last row's control at rest (Borders, Accent)
• ✅ Settings: group titles 4px off the rows' text edge; Density lead-in 16px off
• ✅ Settings > Appearance: density names stepped down by preview height, with dead space under the short ones
• Next (this lane): Settings accounts buttons, switches off-state, profile editor native controls; pages: cloud badge, icon-picker giant tiles, markdown toolbar, changelog duplicate title, chief-inspector orange bars, diff black file bars, quick-surface padding, model-picker popup unstyled in gallery
• Handed off: transcript-density, message-actions, prompt-queue-edit, composer-scroll, activity-indicators, context-menus, newtab lanes, sidebar-cleanup

Summary

• The floating Undo/Redo/Reset bar on Appearance/Theme is sticky, and sticky stops at the scroller's content box, so it sat 16px above the 64px end padding and covered the last row's control even at rest. Its offset now reaches into that padding (--content-pad-end), so it rests 16px above the pane's edge.
• Group titles and the Density lead-in start on the rows' text edge (16px; 10px under 640px), not 12px / 0px.
• Density tiles: each preview takes the tile's slack, so all five names sit on one line under equal-size previews.

Screenshots

Before	After

Testing

• bun test src/pages/settings: 211 pass, 0 fail.
• scripts/web-lint.sh: only the base warning in cv-user__image-failed (not touched here), red on base.

Observed / Not run

• Observed: Linux gallery before/after captures (Chromium, dark, 16x9), attached.
• Not run: light mode and the Mac app (CSS only, no native change).

Changelog

• Fixed: Settings' Undo bar no longer covers the last setting, and the Density tiles and group titles line up.

🤖 Generated with Claude Code

Agent session: huge-blue