feat(apps): MagicMirror as a Void app (#/mirror, mirror.hynesy.com)

Embed MagicMirror² (CT 111) via the shared embedView factory, exposed at
mirror.hynesy.com through Traefik + CF Access. Traefik mirror-frame middleware
swaps MM's X-Frame-Options for a CSP frame-ancestors allowing the Void origins.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/app.js

@@ -29,6 +29,7 @@ const VIEWS = {
   'ai-usage':      () => import('./views/aiusage.js'),
   obd2:            () => import('./views/obd2.js'),
   links:           () => import('./views/links.js'),
+  mirror:          () => import('./views/mirror.js'),
   settings:        () => import('./views/settings.js'),
   jobs:            () => import('./views/jobs.js')
 };