fix: scope PWA service workers to prevent cross-app interference

When multiple SPAs share the same origin (e.g., /sortir/ and /castle/
on demo.aiolabs.dev), their service workers conflict. Each app's
workbox now scopes its navigateFallback with navigateFallbackAllowlist,
and the main app excludes standalone paths via navigateFallbackDenylist.

- Main app: denylist /sortir/ and /castle/ from its service worker
- Sortir: allowlist only /sortir/ paths, fallback to activities.html
- Castle: allowlist only /castle/ paths, fallback to castle.html
- Icon paths use relative URLs (work with any base path)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vite.config.ts

@@ -23,7 +23,9 @@ export default defineConfig(({ mode }) => ({
       workbox: {
         globPatterns: [
           '**/*.{js,css,html,ico,png,svg}'
-        ]
+        ],
+        // Don't intercept standalone app paths — they have their own service workers
+        navigateFallbackDenylist: [/^\/sortir\//, /^\/castle\//],
       },
       includeAssets: [
         'favicon.ico',