The accounts list is keyboard-first: j/k move between rows, enter opens one #10430

One sentence: the accounts list answers to the keyboard the way the waves list does (#10411), so the owner can clear it without the mouse.

Done:

• [x] Every row in src/web/pages/accounts.ts is built with nav: true so j/k move between rows and enter opens one; no new component class, no new script.
• [x] A new test/keys-accounts.test.ts renders the page and asserts the rows carry the nav marker (copy the shape of test/keys-waves.test.ts); it fails without the change.
• [x] The test file is listed in scripts/gate.ts if the gate still needs it (check how test/keys-waves.test.ts is listed).
• [x] bun scripts/design-lint.ts and bun test test/keys-accounts.test.ts pass; docs/features/hotkey-hints.md needs no change unless the hint text does.

Files: src/web/pages/accounts.ts, test/keys-accounts.test.ts Risks: touches src/web/; the marker must not change the markup for readers without JavaScript. One page only, so it never clashes with the sibling keyboard issues. Suggested: torque (its #10411 is the pattern).

Parked by the crew: the check stayed red through 2 automatic tries (pull #10501 closed; its branch scout/10430-the-accounts-list-is-keyboard-first-j-k at b095d58acc02 keeps the work so far). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Reviewed pull #10646 at its head: ticked Every row in src/web/pages/accounts.ts is built with nav: true so j/k move between rows and enter opens one; no new component class, no new script.; A new test/keys-accounts.test.ts renders the page and asserts the rows carry the nav marker (copy the shape of test/keys-waves.test.ts); it fails without the change.; The test file is listed in scripts/gate.ts if the gate still needs it (check how test/keys-waves.test.ts is listed).; bun scripts/design-lint.ts and bun test test/keys-accounts.test.ts pass; docs/features/hotkey-hints.md needs no change unless the hint text does..