ui: overlay spacing fixes, footer modes, spawn position, focus rings

- Remove focus ring from overlay elements (global outline:none on *)
- Remove focus ring on settings titlebar buttons
- Fix settings titlebar: buttons flush to right edge, no gap
- Overlay list padding: symmetric 6px sides, no top/bottom
- Grid view padding: 4px top, 2px bottom (was 4/10)
- Section header padding: 6px top (was 12px)
- Footer: 48px height (was 40px), 6px margin-top in idle mode
- Footer ql mode: 6px spacer, no hints/border, only when quick_launch
- Footer hints: centered via transform, white-space nowrap
- Overlay spawn position: 25% from top (was 30%)