feat(FN-1118): add mobile sharing and deep-link managers

- Implement ShareManager with native Capacitor sharing, web share fallback, and clipboard fallback plus typed share lifecycle events
- Implement DeepLinkManager with native appUrlOpen and browser hash listeners, URL parsing for fusion schemes and universal links, and error events
- Wire plugin exports and initializePlugins support for share/deepLinks options, and configure Capacitor iOS/Android fusion URL schemes
- Add comprehensive Vitest coverage for sharing and deep-link behavior and document usage in the mobile package README

packages/dashboard/capacitor.config.ts

@@ -13,6 +13,8 @@ const config: CapacitorConfig = {
     // to the backend at the configured server url.
     url: process.env.FUSION_BACKEND_URL || undefined,
     cleartext: true, // Allow HTTP connections to local dev servers
+    iosScheme: "fusion",
+    androidScheme: "fusion",
   },
   plugins: {
     SplashScreen: {