Add Nebula Shell v0 prototype and redesign

Introduce a working v0 Nebula Shell prototype (Tauri frontend) and redesign docs. Adds a complete frontend under src/ (views: home, lock, library, settings, overlays), core adapters (input, nav, passkey, router, state), global styles and shell guidelines, and view-specific HTML/CSS/JS. Update README with prototype notes, install/run/build instructions and controller testing tips. Update package.json to add dev/build scripts and add @nebulaproject/core as a dependency. Also include a detailed REDESIGN_DOCUMENTATION.md describing the Xbox-inspired horizontal dashboard, component patterns, and developer notes.

package.json

@@ -4,9 +4,14 @@
   "version": "0.1.0",
   "type": "module",
   "scripts": {
+    "dev": "tauri dev",
+    "build": "tauri build",
     "tauri": "tauri"
   },
   "devDependencies": {
     "@tauri-apps/cli": "^2"
+  },
+  "dependencies": {
+    "@nebulaproject/core": "^0.1.3"
   }
 }