fix: repair cross-package bugs so tests and typecheck pass

[stooit]

Summary

Fixes all failing tests and eliminates all type errors in the monorepo. The acceptance gate bun test && npx tsc --noEmit now passes: 13 pass / 0 fail, tsc exit 0 (baseline was 4 pass / 9 fail, 5 TS errors).

Bugs spanned all three packages (packages/ui, packages/utils, apps/web) plus root test config.

Fixes

#	File	Root cause	Fix
1	bunfig.toml	environment = "happy-dom" is a no-op in bun, so DOM globals were absent when running bun test from the repo root → ReferenceError: document is not defined in all UI tests.	Preload the existing happy-dom setup file.
2	apps/web/src/lib/api.ts	Imported useThrottle from @e2e/utils, but the hook was renamed to useDebounce (TS2305).	Import/re-export the correct name; merged the duplicate import.
3	packages/ui/.../Button.tsx	Icon-only button had no accessible name; test asserts an aria-label-derived name is present.	Forward aria-label; provide a fallback accessible name for icon-only buttons with a dev warning when unlabelled [WCAG 2.2 SC 4.1.2].
4	packages/ui/.../DataTable.tsx	Stale-closure bug: separate sortKey/sortDir state meant second-click descending sort read a stale value.	Collapse into a single state object with a functional updater (atomic key+dir).
5	packages/utils/.../date.ts	en-AU Intl widens a numeric day to 01, so formatDate(1 Mar 2024) returned 01/03/2024; test expects day-first single-digit 1/03/2024.	De-pad the day part via formatToParts.
6	tsconfig.json	bun:test unresolved (TS2307) — bun-types lives outside node_modules/@types/ so it isn't auto-included.	Add explicit "types": ["bun-types"] with an explanatory comment.

Assumptions & notes

• No test files, package.json, or lockfile were modified; no dependencies added — per task constraints (verified via git diff --name-only).
• tsconfig.json "types" array disables auto-inclusion of other @types/* packages. @types/react still resolves via module imports and typecheck is clean; a comment was added so future @types/* additions aren't silently ignored.
• The DataTable change goes slightly beyond a one-line functional updater (collapses key+dir into one object). It's internal-only (no Props/API change), makes the new-column path atomic, and produces identical output for all tested sequences. Reviewed as justified and low-risk.
• The console.warn seen during the test run is expected — a test exercises the unlabelled icon-only Button path.

Verification

• bun test → 13 pass, 0 fail
• npx tsc --noEmit → exit 0
• Independent code review completed: verdict COMMENT, no blockers.

Out of scope (pre-existing, flagged for follow-up)

• DataTable sortable <th> is mouse-only (no keyboard handler) — pre-existing WCAG 2.2 SC 2.1.1 gap.
• formatDate (4-digit year) vs formatDateTime (dateStyle: "short", 2-digit year) inconsistency — pre-existing.