fix: repair cross-package bugs so all tests and typecheck pass

[stooit]

Summary

Fixes all 5 failing tests and all TypeScript errors across the monorepo. bun run test → 13 pass / 0 fail; npx tsc --noEmit → clean (exit 0). No test files or dependencies were modified.

The bugs spanned three packages plus a tsconfig gap:

• apps/web/src/lib/api.ts — stale import. The hook was renamed to useDebounce in @e2e/utils, but this file still imported useThrottle (TS2305). Fixed the import and kept the public useSearchDebounce alias that apps/web/test/api.test.ts asserts on. Merged the duplicate @e2e/utils import while in there.
• packages/ui Button — the ariaLabel prop was destructured but never applied to the element. Icon-only buttons now receive an aria-label (WCAG 4.1.2), with a non-production console.warn when one is omitted. Text buttons resolve to undefined, so React omits the attribute and existing behaviour is unchanged.
• packages/utils formatDate — was producing month-first / mixed-padding output. Now emits a self-consistent day-first AU short date (1/3/2024) with a 4-digit year. formatDateTime left untouched.
• tsconfig.json — added "types": ["bun-types"] so bun:test resolves during typecheck (removes 4 TS2307 errors). bun-types was already a devDependency — no new dependency added.

Verification

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

Assumptions & notes

• The "Button" aria-label fallback guarantees a non-empty accessible name to satisfy the test that renders a label-less icon button (Button.test.tsx:28). A discriminated union making the label mandatory would break that unmodifiable test, so a runtime fallback + dev warning is the intended shape. Real call sites should still pass explicit labels.
• DataTable.tsx carries a BUG: stale closure comment but all its tests pass — handleSort is recreated each render and clicks flush separately, so sortDir is current. Left unchanged as it is not a live defect and no test requires it.
• The dependabot vulnerability warning on push relates to pre-existing dependencies on the default branch and is out of scope for this test-fix task.

Reviewed for correctness/minimality via the review agent; both the renamed public export and the permissive types array were confirmed to suppress nothing legitimate.