## What & why
Fixes **PHP-LARAVEL-41** — `TypeError: addEventListener is not a
function` on Safari 13.1.2 / macOS 10.13.
### Root cause
`MediaQueryList.addEventListener` does not exist on Safari <14 (and
other legacy browsers) — the property is `undefined`; those engines only
expose the deprecated `addListener`. `initializeTheme()` runs at app
boot (`resources/js/app.tsx`) and called:
```ts
mediaQuery()?.addEventListener('change', handleSystemThemeChange);
```
The `?.` guarded a **null** query but not the **missing method**, so the
call threw during module evaluation, aborting the rest of boot
(`initializeChartColorScheme`, `createInertiaApp`) → the whole React app
failed to mount (white screen) for those users. `use-mobile.tsx` had the
same latent crash for any component using `useIsMobile`.
## Changes (one concern per commit)
1. **fix(appearance): support MediaQueryList change events on legacy
Safari** — add `resources/js/lib/media-query.ts`
(`addMediaQueryListener` / `removeMediaQueryListener`) that fall back to
`addListener` / `removeListener` when the modern API is absent, and
route the `prefers-color-scheme` (`use-appearance`) and
mobile-breakpoint (`use-mobile`) subscriptions through them. Colocated
Vitest test covers both the modern and legacy-fallback branches for add
and remove.
2. **harden: no-op when neither API is present** — guard the deprecated
fallback with a `typeof … === 'function'` check so a hypothetical
`MediaQueryList` exposing neither API silently no-ops instead of
re-introducing the crash. (Reviewer recommendation.)
Modern-browser behavior is byte-for-byte unchanged (the modern path is
taken whenever `addEventListener` exists); the only added cost is a
`typeof` check.
## Verification
- `vendor/bin/pint`-equivalent for JS: Prettier + ESLint clean on all
changed files.
- Vitest: `resources/js/lib/media-query.test.ts` covers modern + legacy
+ neither-API branches. (CI runs `bun run test`.)
- Reviewed by two independent agents (architecture + product): both
concluded **ship it**, no must-fix. Confirmed no other
`matchMedia(...).addEventListener('change')` call sites were missed
(`account-balance-card.tsx` and `welcome.tsx` only read `.matches`),
correct add/remove pairing preserved, and no modern-browser regression.
## Follow-up (out of scope, flagged for awareness)
- The Vite build sets no explicit `build.target`/browserslist, so the
default baseline is Safari 14. This PR stops the reported **boot**
crash, but lazily-loaded page chunks could still `SyntaxError` on
navigation for Safari 13 users. Full Safari-13 support would need an
explicit lower build target — a broader change with its own risk, left
as a separate follow-up.