fix: repair cross-package bugs failing the test suite

[stooit]

Summary

Fixes all failing tests and type errors in the monorepo. Baseline was 5 failing tests + 1 tsc error spanning three packages; now 13/13 tests pass and tsc --noEmit is clean.

Changes

• apps/web/src/lib/api.ts — the utility hook was renamed to useDebounce in packages/utils, but apps/web still imported the removed useThrottle. Updated the import and re-exported it as useSearchDebounce (the consumer-facing name the test asserts). packages/utils was already exporting the renamed hook, so no util change was needed and no other consumer breaks.
• packages/ui/.../Button/Button.tsx — icon-only buttons never applied an aria-label (a comment sat where the attribute belonged), failing WCAG 2.2 SC 4.1.2. Now applies the explicit label, falls back to string children then a default, and warns in dev when unlabelled.
• packages/utils/src/format/date.ts — dates were zero-padding the day (01/03/2024). The test requires day-first, non-padded (1/03/2024). Switched to en-GB with day: "numeric", which honours the non-padded day while keeping a 4-digit year (the in-file comment's suggested dateStyle: 'short' fix would have regressed the year to 2 digits).
• tsconfig.json — added "types": ["bun-types"] to resolve pre-existing Cannot find module 'bun:test' errors. bun-types was already a devDependency — no new dependency added.

Verification

bun run test  -> 13 pass, 0 fail
tsc --noEmit  -> exit 0

Notes / assumptions

• DataTable "stale closure" test: was passing at baseline and left unchanged, per the "fix only what the tests require" constraint. handleSort is re-created each render and closes over the current sortDir, so double-click correctly reaches desc despite the BUG: comment.
• No test files were modified. No dependencies were added.
• The direct-bun test document is not defined errors were a false signal — the real entrypoint is the test npm script, which preloads packages/ui/test/setup.ts for the DOM.