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/grid/SpotlightLandscapeLayout.module.css

@@ -43,3 +43,17 @@ unconditionally select the container so we can use cq units */
   inline-size: 180px;
   block-size: 135px;
 }
+
+/* On a landscape phone the fixed 180px filmstrip rail squeezes the spotlight to
+   a sliver; shrink the rail (keeping the 4:3 tile ratio) to give the spotlight
+   room. Desktop landscape (height > 400px) is unaffected. */
+@media (max-height: 400px) {
+  .layer {
+    --grid-slot-width: 132px;
+  }
+
+  .grid > .slot {
+    inline-size: 132px;
+    block-size: 99px;
+  }
+}