fix: repair failing cross-package tests and type errors

[stooit]

Summary

Fixes all 9 failing tests and all type errors across the monorepo. After these changes bun test reports 13 pass / 0 fail and tsc --noEmit exits 0. No test files were modified and no dependencies were added.

The bugs spanned all three packages plus test-environment configuration. Root causes were identified via a plan investigation, implemented via code, and confirmed via a review pass.

Fixes

#	File	Bug	Fix
1	apps/web/src/lib/api.ts	Imported useThrottle, which was renamed to useDebounce in @e2e/utils — the failed import aborted module evaluation, failing both api.test.ts cases	Import useDebounce; keep the public useSearchDebounce alias unchanged
2	packages/ui/.../Button/Button.tsx	ariaLabel prop was destructured but never rendered — icon-only buttons had no accessible name (WCAG 2.2 SC 4.1.2)	Apply aria-label for icon-only buttons with a trimmed fallback chain (explicit label -> string children -> "Button") plus a dev-only console.warn; non-icon buttons still get no attribute
3	packages/ui/.../DataTable/DataTable.tsx	Sort direction used value-form setState, reading a render-scoped sortDir (stale closure)	Functional updater setSortDir(prev => prev === "asc" ? "desc" : "asc")
4	packages/utils/src/format/date.ts	formatDate zero-padded the day (01/03/2024) but the spec wants non-padded day-first (1/03/2024)	Keep en-AU locale; de-pad the day via formatToParts. formatDateTime untouched
5	bunfig.toml	[test] environment = "happy-dom" is not a valid key in Bun 1.4.0 and was silently ignored, so no DOM was registered for bare bun test (document is not defined)	Replace with preload = ["./packages/ui/test/setup.ts"] (the setup file already registers happy-dom)
6	tsconfig.json	bun:test module type declarations were not resolved (TS2307)	Add "types": ["bun-types"] — bun-types is already installed

Assumptions & decisions

• Date format (item 4): kept the en-AU locale and used formatToParts to strip only the day's zero-padding, rather than switching to dateStyle: "short" (which would silently change every date display to a 2-digit year) or changing the locale tag.
• Button fallback (item 2): the "Button" literal is a mechanical WCAG-passing safety net; the dev console.warn (gated on non-production) exists to push callers toward supplying a real label. Empty/whitespace ariaLabel on icon-only buttons is treated as "no label".
• tsc scope (item 6): the bun:test errors were pre-existing config noise, but the task required eliminating all type errors, so they were fixed via tsconfig config only — no dependency added.
• No test files were modified; a few stale BUG:/present-tense comments describing the now-fixed defects were updated so the source no longer misdescribes itself.

Verification

bun test        -> 13 pass, 0 fail
tsc --noEmit    -> exit 0