Accessibility pass over every route

Record the pass in docs/A11Y.md: keyboard, focus, names and roles, text
contrast per token pair, hit targets and reduced motion for each route.

Fix the four medium findings, each with a regression test:
- Muted text in neutral-600 (3.5-4.0:1) is now neutral-700; a contrast
  test checks every text token pair and the tokens stylesheets use.
- The bottom bar's focus ring is on-accent, not grape on the dark bar.
- The Kitchen reading text-size ring sits inside the clipped pill.
- The tablet-portrait Quest log chips keep the 44 px tap minimum.

Low findings are listed as follow-ups.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/plan/PlanPage.module.css

@@ -203,7 +203,7 @@
 
 .swapping .dinner,
 .swapping .startBy {
-  color: var(--color-neutral-600);
+  color: var(--color-neutral-700);
 }
 
 .rebuildCell {