fix: repair cross-package bugs to make all tests pass and clear type errors

[stooit]

Summary

Fixes all failing tests (13/13 now pass) and eliminates all TypeScript errors (tsc --noEmit exit 0) across the monorepo. Four cross-package bugs plus one pre-existing tsconfig gap were addressed. No test files were modified and no dependencies were added.

Fixes

• Renamed hook import (apps/web/src/lib/api.ts): the utils hook was renamed useThrottle → useDebounce, but apps/web still imported the old name. Updated the consumer to import useDebounce and re-export it as useSearchDebounce (the public name the test depends on).
• Button accessibility (packages/ui/src/components/Button/Button.tsx): pass aria-label through to the rendered <button> so icon-only buttons have an accessible name (WCAG 2.2 SC 4.1.2), with a fallback + dev-only warn when missing.
• DataTable stale closure (packages/ui/src/components/DataTable/DataTable.tsx): sort handler read sortDir from a stale closure; collapsed into one atomic sort: { key, dir } state via a pure functional updater — StrictMode-safe.
• AU date format (packages/utils/src/format/date.ts): formatDate renders day-first without a leading zero (e.g. 1/03/2024) using Intl.formatToParts with en-AU.
• tsconfig types (tsconfig.json): registered bun-types so bun:test resolves, clearing 4 pre-existing TS2307 errors (config registration; bun-types was already a devDependency).

Verification

• bun run test → 13 pass / 0 fail
• bunx tsc --noEmit → exit 0
• No test files modified; independent review confirmed correctness and no regressions.

Notes

• Ran tests via the project's bun run test script (applies the happy-dom setup preload; a bare bun test misses it and surfaces spurious document is not defined errors).
• Some tests encode specific contracts (e.g. day-first /^1/ date format); implementations follow the tests as written since test files were off-limits.

Follow-ups (out of scope)

• DataTable sortable <th> is mouse-only (pre-existing WCAG 2.1.1 gap).
• Consider a discriminated-union prop type to require aria-label when iconOnly.