Closes 9.2 (desktop reading width).
- (app)/+layout.svelte wraps detail routes (/lists/[id], /tasks/[id],
/notes/[id]) in a max-w-2xl mx-auto container at the md breakpoint
and up. Mobile (<md) keeps the existing full-width layout — the
wrapper only kicks in via md:max-w-2xl. The shopping session
(/lists/[id]/session) is explicitly excluded so the immersive mode
still occupies the whole viewport.
- A new readingRoutePattern lives alongside the existing
detailRoutePattern so the two concerns stay independently testable
(detail = hide global top bar; reading = cap width).
- RW-01..RW-03 in tests/e2e/reading-width.test.ts measure the
bounding box of [data-testid="reading-column"] under 1280px and
390px viewports, and confirm the wrapper is absent from /session.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
