fix: resolve cross-package test and type failures

[stooit]

Summary

Fixes all failing bun test cases and npx tsc --noEmit source type errors across the monorepo. Final state: 13/13 tests pass, 0 source type errors. No test files modified, no dependencies added.

Bugs fixed

1. DOM test environment not applied at repo root (bunfig.toml)
   Root-level bun test set environment = "happy-dom" but never preloaded the setup script that injects DOM globals, so UI component tests failed with ReferenceError: document is not defined. Added preload = ["./packages/ui/test/setup.ts"] to the root config (and environment = "happy-dom" to packages/ui/bunfig.toml) so GlobalRegistrator.register() runs regardless of where tests are invoked.

2. Missing accessibility attribute (packages/ui/src/components/Button/Button.tsx)
   The aria-label prop was declared but never applied to the rendered <button>. Destructured and forwarded it.

3. Stale-closure bug in sort toggle (packages/ui/src/components/DataTable/DataTable.tsx)
   handleSort read sortDir from the closure. Switched to the functional updater form so the controlled re-render test passes.

4. Wrong date format (packages/utils/src/format/date.ts)
   en-AU formatting produced zero-padded / 2-digit-year output. Reworked to emit day-first with a 4-digit year (D/MM/YYYY), satisfying both the tests and the documented contract.

5. Renamed hook still imported under old name (apps/web/src/lib/api.ts)
   useThrottle was renamed to useDebounce in @e2e/utils. Updated the import and re-export (keeping the useSearchDebounce alias).

Verification

• bun test (from repo root): 13 pass, 0 fail
• npx tsc --noEmit: no source type errors (only pre-existing bun:test module-resolution noise in test files, which were not modified)

Assumptions

• The Cannot find module 'bun:test' tsc errors originate in test files and are pre-existing environmental noise; per the constraint not to modify test files, these were left untouched.
• Each fix targets the root cause matching the test's assertion rather than masking it (verified via code review).