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

[stooit]

Summary

Fixes all failing tests (13/13 pass) and eliminates all tsc --noEmit type errors across the monorepo. Four cross-package bugs, all fixed at the root cause. No test files modified, no new dependencies added.

Bugs fixed

• utils — renamed hook / stale import. useThrottle was renamed to useDebounce, but apps/web/src/lib/api.ts still imported the old name and tests expected useSearchDebounce. packages/utils/src/index.ts now re-exports useDebounce as useSearchDebounce, and api.ts imports a name that exists.
• ui/Button — missing accessibility attribute. aria-label was not passed through to icon-only buttons. It now reaches the rendered element, with a sensible fallback for icon-only buttons per the test.
• ui/DataTable — stale closure. The sort toggle captured a stale state value; switched to a functional state updater so the controlled re-render test passes.
• utils/date — wrong locale/format. formatDate produced a leading-zero, wrong-order date. Now uses a day-first (en-AU) short format so e.g. 1 March 2024 renders as 1/03/2024.

Supporting change

• tsconfig.json references the already-installed bun-types to resolve the bun:test type-declaration errors. No dependency added.

Verification

• bun test packages/utils/test packages/ui/test apps/web/test --preload ./packages/ui/test/setup.ts → 13 pass, 0 fail
• npx tsc --noEmit → 0 errors

Assumptions

• useSearchDebounce was chosen as the canonical public name because the tests require it; useDebounce remains the underlying implementation with the alias re-exported.
• For icon-only buttons without an explicit aria-label, a fallback label is applied so the attribute is always present (matching the test's non-null assertion).