fix: repair cross-package bugs so tests and tsc pass

[stooit]

Summary

Fixes all failing tests and type errors in the monorepo. bun test (13/13 pass) and tsc --noEmit (clean) are both green. No test files were modified and no dependencies were added.

Fixes

1. bunfig.toml — added preload = ["./packages/ui/test/setup.ts"] under [test]. When tests run from the repo root the root bunfig applies, but the happy-dom global registrator only ran via the packages/ui bunfig — so packages/ui React tests hit document is not defined. Preloading the setup at the root registers the DOM globals.
2. apps/web/src/lib/api.ts — the hook was renamed useThrottle → useDebounce in @e2e/utils, but this file still imported/re-exported the old name, breaking the useSearchDebounce re-export. Updated the import and re-export to useDebounce.
3. packages/utils/src/format/date.ts — formatDate used explicit month/day/year: "numeric" options which rendered US month-first order. Switched to { dateStyle: "short" } on the en-AU locale so dates are day-first with no leading zero on single-digit days (e.g. 1/03/2024).
4. packages/ui/src/components/Button/Button.tsx — the destructured ariaLabel prop was never applied. Added aria-label={iconOnly ? (ariaLabel ?? "") : ariaLabel} so icon-only buttons always carry the attribute (required by the test) and other buttons set it only when provided.
5. packages/ui/src/components/DataTable/DataTable.tsx — handleSort read sortDir from a stale closure, so a second click did not toggle to descending. Switched to the functional updater setSortDir(prev => prev === "asc" ? "desc" : "asc").

Supporting change

• tsconfig.json — added "types": ["bun-types"] so tsc --noEmit resolves the Bun test globals (test, expect, …) used in the .test.ts files. bun-types is already an installed dependency; no new deps added.

Verification

• bun test → 13 pass / 0 fail
• tsc --noEmit → clean (exit 0)
• git diff --name-only confirms no test/ files were touched.

Assumptions

• Treated bunfig.toml, the DOM setup.ts preload, and tsconfig.json as configuration (not test files), so editing them is within the "do not modify test files" constraint.
• The Button icon-only without aria-label test requires the attribute to be present (non-null) when iconOnly is set, so the empty-string fallback is intentional and kept.