fix: repair cross-package bugs breaking tests and typecheck

[stooit]

Summary

Repairs all failing tests and type errors in the monorepo. bun test → 13 pass / 0 fail; bunx tsc --noEmit → clean (exit 0). Bugs spanned all three packages (packages/ui, packages/utils, apps/web) plus build config.

Fixes

#	File	Bug	Fix
1	apps/web/src/lib/api.ts	Imported/re-exported a hook by a stale name (useThrottle); the real export in packages/utils is useDebounce, causing SyntaxError: export 'useSearchDebounce' not found	Import useDebounce, keep the public useSearchDebounce alias so no caller breaks
2	bunfig.toml	Root config used [test].environment — not a real bun option, so it silently did nothing and DOM globals were missing → ReferenceError: document is not defined in all UI tests	Use the supported preload mechanism to load the happy-dom setup so bare bun test from the repo root has a DOM
3	packages/ui/.../Button.tsx	Icon-only button rendered no accessible name; test expects a non-null aria-label	Resolve an aria-label (explicit prop → string children → "Button" floor) with a dev-only warning when an icon-only button has no explicit label
4	packages/ui/.../DataTable.tsx	Stale closure in the sort handler — setSortDir(sortDir === ...) reads the render-time captured value; two toggles in one batch produce the wrong direction and wrong aria-sort	Functional updater: setSortDir(prev => prev === "asc" ? "desc" : "asc")
5	packages/utils/.../date.ts	formatDate emitted a zero-padded day (01/03/2024); test requires an unpadded, day-first en-AU format	Use Intl.DateTimeFormat("en-AU").formatToParts to strip the day's leading zero → 1/03/2024
6	tsconfig.json	Four TS2307 errors resolving bun:test etc.	Add bun-types (+react) to compilerOptions.types

Constraints honoured

• No test files modified, no dependencies added (verified: git diff touches no *.test.* or package.json).
• Fixed only what the tests require; stale BUG: diagnostic comments removed from edited files for consistency.

Assumptions / notes

• aria-label="Button" fallback is a compliance floor to satisfy the test (Button.test.tsx:24 renders an icon-only button with no label and expects it to still render). A type-level "require aria-label for iconOnly" was rejected because it would make the test file itself a type error. The dev warning mitigates the weak label.
• DataTable stale-closure fix is confirmed correct on inspection but not directly exercised by the current suite (no test clicks a sortable header twice) — it prevents a real defect the task brief flagged and removes flakiness risk under future React versions / userEvent.
• Out-of-scope defects noted, not changed (would require behavioural/test changes): DataTable sort headers are mouse-only (no keyboard handler/role — WCAG 2.1.1/4.1.2); formatDate and formatDateTime disagree on year width (pre-existing).