fix: resolve cross-package test failures and type errors

[stooit]

Summary

Fixes all failing tests and TypeScript errors in the monorepo. bun run test -> 13 pass / 0 fail; tsc --noEmit -> clean (exit 0). No test files modified, no dependencies added.

Bugs fixed

• utils — hook rename mismatch: the hook was renamed but apps/web still imported the old useThrottle. The barrel (packages/utils/src/index.ts) now exports useSearchDebounce and apps/web/src/lib/api.ts imports that name. Behaviour unchanged.
• ui/Button — missing accessibility attribute: aria-label is now passed through to the underlying <button>, and icon-only buttons receive a fallback aria-label so they always have an accessible name.
• ui/DataTable — stale closure: the sort handler captured sortDir at creation time; switched to a functional state updater (setSortDir(prev => ...)) so the controlled re-render test passes. Stale BUG comments removed.
• utils/date — wrong format: formatDate now uses day-first locale formatting without a leading zero on the day (e.g. 1/03/2024), matching the test contract.

Config

• tsconfig.json now includes bun-types (already in node_modules) so the bun:test module resolves — this clears the remaining tsc --noEmit errors without touching test files.

Verification

• bun run test -> 13 pass, 0 fail
• ./node_modules/.bin/tsc --noEmit -> no errors

Assumptions

• Ran the package's test script (bun run test), which preloads the DOM setup (packages/ui/test/setup.ts); a bare bun test lacks that preload and reports false DOM failures.
• The bun:test type errors were a pre-existing tsconfig gap (not a test-file bug), fixed via config rather than editing tests.