fix: repair failing tests and type errors across monorepo

[stooit]

Summary

Fixes all failing tests and eliminates all tsc --noEmit type errors across the monorepo. The bugs spanned four packages plus test-harness and build config.

Before: 4 pass / 9 fail · tsc --noEmit exit 2 (4 errors)
After: 13 pass / 0 fail · tsc --noEmit exit 0

Root causes & fixes

File	Bug	Fix
bunfig.toml	environment = "happy-dom" is a Jest/Vitest key that Bun silently ignores, so @testing-library/react ran with no DOM → document is not defined (6 failures).	Replaced with preload = ["./packages/ui/test/setup.ts"], which actually registers the happy-dom global.
apps/web/src/lib/api.ts	Imported useThrottle from @e2e/utils, but the hook was renamed to useDebounce → SyntaxError: export not found.	Point the import at useDebounce. The public useSearchDebounce name is unchanged, so no consumer breakage.
packages/ui/.../Button.tsx	Icon-only buttons had no accessible name; aria-label was never rendered onto the element.	Render aria-label on the element, falling back to string children before a generic "Button"; dev-only console.warn when an icon-only button lacks a label. [WCAG 2.2 SC 4.1.2]
packages/utils/.../date.ts	en-AU Intl.DateTimeFormat zero-pads the day (01/03/2024); test expects day-first, unpadded.	Use formatToParts and Number() the day → 1/03/2024 (D/MM/YYYY). Hardcoded en-AU, locale-proof.
tsconfig.json	bun-types (already a devDependency) wasn't wired in, so bun:test was unresolvable → 4× TS2307.	Added "types": ["bun-types"] to compilerOptions. No new dependency.

Verification

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

Assumptions / notes

• No test files were modified and no dependencies were added (bun-types was already declared and installed — only the tsconfig wiring was missing).
• The formatDate output 1/03/2024 has asymmetric padding (unpadded day, zero-padded month) — this is forced by the un-editable test assertion /^1/. It diverges slightly from formatDateTime's format; a follow-up could align them, but that would require changing behaviour the tests pin.
• The Button children-string fallback improves on a naive hardcoded "Button" (which would have masked real accessible names), but full node-tree name recovery is out of scope — passing an explicit aria-label remains the intended API, and the dev warning steers callers there.
• Setting types in tsconfig disables automatic @types/* inclusion; harmless today (React types resolve via explicit import), but a future @types/node etc. would need appending to that array.

🤖 Generated autonomously.