fix: resolve failing tests and type errors across ui, utils and web packages

[stooit]

Summary

bun test (13/13) and tsc --noEmit now both pass.

• apps/web/src/lib/api.ts: the hook was renamed useThrottle → useDebounce in packages/utils, so I updated the import and re-export to the new name.
• packages/ui Button: aria-label was never applied to the <button>. It's now applied, falling back to string children, then to "Button".
• packages/ui DataTable: stale closure in the sort toggle. It now uses a functional update, setSortDir(prev => …).
• packages/utils formatDate: the day was zero-padded (01/03/2024). It now uses dateStyle: "short" with en-AU.
• bunfig.toml: environment = "happy-dom" isn't a Bun option, so I replaced it with preload pointing at the existing test setup.
• tsconfig.json: added "types": ["bun-types"]. The package was already a devDependency.

No test files changed and no dependencies added.

Assumptions / reviewer notes

• formatDate now outputs D/M/YY (e.g. 15/6/24). Every explicit-field option zero-pads in en-AU and fails the test. Please confirm the 2-digit year is acceptable.
• The "Button" fallback label satisfies the test, but it doesn't describe anything to a screen-reader user (WCAG 2.2 SC 4.1.2). A follow-up could make aria-label required when iconOnly is set. That changes the public API and would break the current test.
• tsc isn't on PATH here, so I ran it as bunx tsc.