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

[stooit]

Summary

Fixes all 5 failing tests and 5 type errors across the monorepo. After these changes bun run test reports 13/13 pass and bun run typecheck (tsc --noEmit) exits 0. No test files or package.json were modified.

Changes

Area	File	Fix
Renamed hook	apps/web/src/lib/api.ts	The hook was renamed to useDebounce in @e2e/utils but api.ts still imported useThrottle. Import the real export and keep the useSearchDebounce alias the app/test expect. useDebounce is a genuine trailing-edge debounce, so this is a rename, not a semantic swap.
Accessibility attr	packages/ui/src/components/Button/Button.tsx	aria-label was never forwarded to the <button> element. Now forwarded; for iconOnly buttons it defaults to an explicit label (explicit aria-label is never clobbered), with a dev-only WCAG 2.2 SC 4.1.2 warning. Guard hardened with typeof process !== "undefined" so it can't throw in browsers.
Stale-closure bug	packages/ui/src/components/DataTable/DataTable.tsx	Sort key and direction were two separate useState atoms; on batched clicks the toggle branch read stale state and never fired. Merged into one sort object updated through a single functional updater so key/direction update atomically.
Date format	packages/utils/src/format/date.ts	formatDate produced 01/03/2024 (leading-zero day); the test requires a day-first, unpadded day (1/03/2024). Switched to en-GB with explicit field options. formatDateTime aligned to match (it had drifted to a 2-digit year).
Type config	tsconfig.json	Added bun-types and the apps test glob so apps/web/test typechecks — mirrors the existing packages test pattern, and resolves the bun:test errors.

Assumptions & judgement calls

• Pinned timeZone Australia/Sydney in the date formatters. Load-bearing, not cosmetic: without it the date test fails under non-AEST timezones (e.g. the UTC timestamp renders as 02/03/2024 under Pacific/Auckland). Pinning makes output deterministic regardless of host timezone. Follow-up could make it an opt-in parameter.
• Unpadded day (1/03/2024). Required by the test regex. A follow-up could pad both fields and relax the test if a stricter DD/MM/YYYY convention is preferred (out of scope: would require a test change).
• iconOnly default label + dev warning kept as runtime behaviour. A stricter design would make aria-label a compile-time requirement via a discriminated union; left as a follow-up to avoid widening the public Button API beyond what tests require.

Testing

• bun run test -> 13 pass, 0 fail
• bun run typecheck -> exit 0
• Date formatters verified consistent across UTC, America/New_York, and AU timezones.