fix: resolve failing tests and type errors across monorepo

[stooit]

Before: 9 of 13 tests failed and tsc failed. After: bun test passes 13/13 and bunx tsc --noEmit is clean.

• bunfig.toml: replaced environment = "happy-dom" (Bun ignores it, so root runs gave 'document is not defined') with a preload of packages/ui/test/setup.ts. No new deps.
• Button.tsx: aria-label was destructured but never passed to . Now forwarded; icon-only buttons fall back to string children, then 'Button (missing label)', and warn outside production.
• DataTable.tsx: handleSort now uses the functional setSortDir form. Small hardening; DataTable tests already passed.
• date.ts: formatDate keeps en-AU and drops the day's leading zero (1/03/2024). Day order was already correct.
• apps/web/src/lib/api.ts: imports useDebounce instead of the renamed useThrottle.
• tsconfig.json: added types: [bun-types] (already a devDependency) to fix 'Cannot find module bun:test'.

Assumptions: a test requires unlabelled icon-only buttons to still have an aria-label, hence the fallback (follow-up: make aria-label required for iconOnly at the type level). Tests should run from the repo root. No test files changed, no deps added.