The waves list is keyboard-first: j/k move between rows, enter opens one #10411

The waves page now takes part in the shell's j/k row traversal: j and k move between rows, and enter opens the one you're on.

• What changed: both kinds of row in src/web/pages/waves.ts now carry nav: true. Those are a parsed wave and a waves/*.md file that isn't a wave. The second kind still links to its blob view, so enter does something on every row. The empty page has no rows, so it gets none.
• Tests: test/keys-waves.test.ts seeds two waves and one non-wave file, and expects three data-nav rows. It also expects none on a repository with no waves. Both tests pass. I did not run the new test against the unchanged code to confirm it fails there.
• Checks: tsc and bun scripts/design-lint.ts came out clean and bun scripts/gate.ts printed nothing; I read all three as passing. I ran only the new test file, not the full suite.
• Extra commit: the pre-push hook refused the first push, because it wants a "Try:" line in the commit messages. I added an empty commit carrying one.
• Not done: the single wave page (/waves/:version) is untouched, since the issue only covers the list.

To try it, open /<owner>/<repo>/waves on a repository with waves, then press j, k and enter.

Closes #10402

The waves page now takes part in the shell's j/k row traversal: j and k move between rows, and enter opens the one you're on.

• What changed: both kinds of row in src/web/pages/waves.ts now carry nav: true. Those are a parsed wave and a waves/*.md file that isn't a wave. The second kind still links to its blob view, so enter does something on every row. The empty page has no rows, so it gets none.
• Tests: test/keys-waves.test.ts seeds two waves and one non-wave file, and expects three data-nav rows. It also expects none on a repository with no waves. Both tests pass. I did not run the new test against the unchanged code to confirm it fails there.
• Checks: tsc and bun scripts/design-lint.ts came out clean and bun scripts/gate.ts printed nothing; I read all three as passing. I ran only the new test file, not the full suite.
• Extra commit: the pre-push hook refused the first push, because it wants a "Try:" line in the commit messages. I added an empty commit carrying one.
• Not done: the single wave page (/waves/:version) is untouched, since the issue only covers the list.

To try it, open /<owner>/<repo>/waves on a repository with waves, then press j, k and enter.