fix: resolve failing tests and type errors across monorepo - #290

Summary

bun test && tsc --noEmit now passes: 13 tests pass, 0 fail, and tsc reports no errors.

• bunfig.toml: Bun ignores the environment = "happy-dom" setting. Replaced it with a preload of the existing packages/ui/test/setup.ts (happy-dom global registrator), so document exists in the UI tests.
• apps/web/src/lib/api.ts: imports the renamed useDebounce instead of the removed useThrottle.
• Button.tsx: now forwards aria-label to the button. Icon-only buttons without a label fall back to "" and log a console.warn.
• DataTable.tsx: the sort toggle uses a functional setSortDir update, which fixes the stale closure.
• date.ts: formatDate now produces en-AU D/MM/YYYY with no leading zero on the day, as the test expects (1/03/2024).
• tsconfig.json: added "types": ["bun-types"] (already a devDependency) so tsc can resolve bun:test.

Assumptions and review notes

• No test files were changed and no dependencies were added.
• Button: the empty aria-label fallback exists only because a test requires a non-null attribute on an icon-only button that has no label. An empty label gives no accessible name, so the WCAG 4.1.2 problem is still there. The proper fix is to make aria-label required for iconOnly buttons (a discriminated union) and update that test. That falls outside this task's constraints.
• formatDate: the output changes for days 1–9 (01/… becomes 1/…). The only caller in the repo is the re-export in apps/web.
• DataTable: the DataTable tests already passed once the DOM environment was fixed. The functional update is kept as a correctness fix for the stale closure the task describes.
• Test setup: the happy-dom preload now runs for every package, so happy-dom also replaces fetch in the utils and web tests.