fix(web-ui): remove nav footer star button

[bobleer]

Summary

• Remove the GitHub Star CTA from the navigation footer.
• Delete its one-shot persistence, dedicated styles, locale copy, test, and Appearance part.
• Keep the existing GitHub Star entry in the About dialog and add a regression assertion for the footer.
• Repair stale frontend test contracts exposed by the upstream design-system migration so the full CI suite can run cleanly.

Type and Areas

Type: UI/UX / bug fix

Areas: Web UI navigation footer, Appearance contract, i18n, frontend test contracts

Motivation / Impact

The footer should contain device status and settings without the promotional Star control. Users no longer see the Star button in the navigation footer; the repository entry in About remains available.

Verification

• NODE_OPTIONS=--no-experimental-webstorage pnpm --dir src/web-ui run test:run — 573 files, 4163 tests passed (the option disables Node 26's experimental global Web Storage to match CI behavior)
• pnpm run check:web — passed
• pnpm run i18n:audit — passed with 0 warnings
• pnpm run motion:audit — completed; no finding introduced by this change
• Focused regression suite — 3 files, 37 tests passed

Reviewer Notes

• AI-assisted change; verified with both focused and complete Web UI suites.
• No remote workspace, remote control, Peer Device Mode, or Detached Dispatch behavior changed.
• The About dialog's GitHub Star action is intentionally retained.
• The added test-contract fixes cover Canvas adapter anatomy, an isolated Appearance compiler fixture, and the migrated Appearance Market form-control mock.

Checklist

• This PR is focused and does not include secrets, temporary prompts, generated scratch files, or unrelated artifacts.
• Relevant verification is recorded above, or skipped checks are explained.
• User-facing strings, docs, and locales are updated where applicable.