- Hamburger button: 32x32 -> 44x44 tap target (iOS HIG minimum), SVG icon
20 -> 24px. flex-shrink:0 preserved; spacer keeps the title centered.
- Edge-swipe-to-open-sidebar: edge zone 28 -> 80px, trigger 72 -> 64px, max
vertical 48 -> 56px; removes the _isPwaStandalone() gate in
_onPwaSidebarSwipeStart so the gesture works in a normal mobile browser, not
only the installed PWA. Still _isDesktopWidth()-blocked, touch/pen-only,
interactive-target-excluded, and requires horizontal intent (dx>=64 &&
dx>|dy|*1.5), so scroll/tap won't trigger it.
Known tradeoff (Nathan-approved ship-as-is): in mobile BROWSER the 80px left
edge zone overlaps iOS Safari's back-swipe; degrades gracefully (PWA, the
primary mobile target, has no back gesture).
Verified live at 390x844: hamburger renders 44x44 + tap opens sidebar; a
left-edge swipe opens the sidebar in a non-PWA context. 66 existing mobile/
swipe/titlebar tests pass.
Co-authored-by: kaishi00 <kaishi00@users.noreply.github.com>