fix(lotus): in-call mobile UI fixes (EC audit wave-2)

3-agent survey of the in-call UI at phone width + 2-agent review of the
staged diff. All changes are mobile-gated CSS (mobile-first @media on
Compound tokens), so desktop rendering is provably unchanged.

- CallFooter: wrap the control row and tighten gap/padding at <=500px so
  the buttons (incl. the destructive hangup) can never be clipped by the
  grid's overflow-x:hidden. A loudspeaker button was added to the bar
  without a shed rule, pushing 6-7 lg buttons past the viewport at
  320-500px.
- OneOnOnePortraitLayout: give the 1:1 self-view the same safe-area-aware
  inset as SpotlightExpandedLayout so it clears the home indicator /
  floating footer (was a bare 16px inset). Phone-only layout.
- GridTile: enlarge the always-visible camera-flip control to a 44px touch
  target on coarse pointers (was ~28px).
- ReactionToggleButton: enlarge reaction-picker emoji buttons to 44px at
  <=420px (were ~32px); five still fit a 360px drawer row.
- Tabs: scroll the horizontal tab row on the inline axis (overflow-x) so
  the Settings tabs don't clip in a phone drawer.
- SpotlightLandscapeLayout: shrink the 180px filmstrip rail to 132px on
  short landscape phones (max-height:400px) so the spotlight isn't a sliver.

Gates: tsc 0, prettier clean, affected vitest pass. No TS changed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/button/ReactionToggleButton.module.css

@@ -12,8 +12,10 @@
 
 @media (max-width: 420px) {
   .reactionPopupMenu {
-    --reaction-button-padding: 8px;
-    --reaction-button-fontsize: 16px;
+    /* 20px glyph + 2×12px padding = a 44px square touch target. Five buttons
+       still fit a ~360px drawer row; previously these were ~32px. */
+    --reaction-button-padding: 12px;
+    --reaction-button-fontsize: 20px;
     --reaction-button-gap: 6px;
   }
 }