The next-up page fits a 390 px phone: no sideways scroll, long names wrap #9324

The owner opens /preview-admin/sample/next on a 390 px phone. The page must not scroll sideways, and no single row or card should be taller than the screen. Follow the pattern of test/bets-card-fit.test.ts (#9286).

Done looks like:

• [x] A test renders the repository's next-up page with seeded long content: a 300-character unbroken word, a long title, many rows. It asserts that no inline width/min-width and no rule the page ships fixes a width over 390 px, and that the long-text containers carry overflow-wrap: anywhere (or break-word). It fails without the fix, or, if the page already fits, it pins that.
• [x] Anything it finds is fixed in src/web/pages/next.ts. Any new class is named in docs/design/areas/next-up.md, not docs/DESIGN.md.
• [ ] The pull description links the preview's phone look of /preview-admin/sample/next, and says in one line whether it scrolls sideways.
• [x] bun scripts/design-lint.ts passes. Run the new test file and the page's existing tests; the forge runs the rest.

Files: src/web/pages/next.ts, docs/design/areas/next-up.md, one new test file. Risks: change no route and no data read. Don't touch src/http/api.ts.

Reviewed pull #9366 at its head: ticked A test renders the repository's next-up page with seeded long content: a 300-character unbroken word, a long title, many rows. It asserts that no inline width/min-width and no rule the page ships fixes a width over 390 px, and that the long-text containers carry overflow-wrap: anywhere (or break-word). It fails without the fix, or, if the page already fits, it pins that.; Anything it finds is fixed in src/web/pages/next.ts. Any new class is named in docs/design/areas/next-up.md, not docs/DESIGN.md.; bun scripts/design-lint.ts passes. Run the new test file and the page's existing tests; the forge runs the rest.. left open: The pull description links the preview's phone look of /preview-admin/sample/next, and says in one line whether it scrolls sideways. — The description says it has not confirmed whether the page scrolls sideways, so the one-line statement is missing..

Left open after pull #9366 landed: 1 unticked item remains (The pull description links the preview's phone look of /preview-admin/sample/next, and says in one line whether it scrolls sideways.). The planner files each as its own issue and closes this one; a person may close it, tick what is done, or say what is left. Until then the crew does not pick it again.

Split into #9386. The page work is shipped (8d484d014, test/next-fit.test.ts). The open box asked the pull description to link the owner-taken phone look of /preview-admin/sample/next, which the crew can't fetch (#727). #9386 replaces it with a measured answer: the pull's looks report sideways for each phone page.