feat(formatting): switch prettier to oxfmt

[alx-xo]

Summary

• Replace Prettier config, dependencies, and ESLint formatting enforcement with oxfmt.
• Add Moonshine's oxfmt config with existing generated-file ignores and Tailwind class sorting for src.
• Keep the repo-wide oxfmt rewrite isolated in a separate formatting commit.

A prelude to moving into gram repo. Align our formatting deps and config

Cubic found some preexisting bugs but in the intertest of keeping this PR aligned going to move those to it's own PR. #353

Test Plan

• Formatter/lint gate passes with oxfmt checking 258 files.
• TypeScript type-check passes.
• vitest suite passes 64 tests.

[cubic-dev-ai]

4 issues found across 244 files

Confidence score: 3/5

• There is a concrete user-facing behavior risk in src/components/SegmentedButton/index.tsx: enhancedChildren memoization omits hoveredId, so highlighted state can become stale after interaction.
• Accessibility is also impacted in src/components/WorkspaceSelector/SearchBox.tsx because the icon-only clear button lacks an accessible name (aria-label), which can make the control unclear for assistive technology users.
• Given the medium-severity interaction bug (6/10, high confidence) plus an accessibility issue, this carries some merge risk rather than being a clean low-risk merge.
• Pay close attention to src/components/SegmentedButton/index.tsx, src/components/WorkspaceSelector/SearchBox.tsx, src/components/Table/context/tableProvider.tsx, and src/components/LanguageIndicator/index.tsx - fix stale memo state first, then address accessibility and minor cleanup issues.

<sub>Partial review: This PR has more than 100 files, so cubic reviewed the highest-priority files first.
For a deeper review of large PRs, comment @cubic-dev-ai ultrareview. Learn more.

Fix all with cubic | Re-trigger cubic</sub>

[cubic-dev-ai]

6 issues found across 244 files

Confidence score: 3/5

• src/components/ExternalPill/index.tsx opens external links with _blank but without rel="noopener noreferrer", which leaves a concrete reverse-tabnabbing hole if a linked page is malicious. Add the rel attributes before merging to close the security gap.
• src/components/Tabs/index.tsx and src/components/AppLayout/useAppLayoutKeys.ts both have state-selection/toggle edge cases (|| fallback and captured !collapsed) that can mis-handle valid tab IDs or drop rapid keyboard toggles, leading to inconsistent UI behavior. Switch to nullish coalescing for tab fallback and a functional state updater for collapse toggles before merge.
• src/components/KeyHint/index.tsx uses a clickable div for dismiss, so keyboard and assistive-technology users may be unable to trigger the action reliably. Replace it with a semantic button (or equivalent keyboard-complete control) before merging.
• src/components/KeyHint/index.tsx and src/components/UserAvatar/index.tsx include smaller rendering correctness issues (keyless mapped fragments and possible undefined fallback colors for non-letter initials) that can produce warnings or visual glitches in edge cases. Add stable keys and guard the color index calculation to de-risk UI polish regressions.

<sub>Tip: instead of fixing issues one by one fix them all with cubic
Partial review: This PR has more than 100 files, so cubic reviewed the highest-priority files first.
For a deeper review of large PRs, comment @cubic-dev-ai ultrareview. Learn more.

Re-trigger cubic</sub>