feat(06-01): scaffold apps/desktop as @tessera/desktop Tauri 2.x project

- Create Tauri project structure with Cargo.toml, tauri.conf.json, build.rs
- Implement lib.rs with store plugin and server URL navigation on startup
- Configure capabilities with core:default and store:default permissions
- Set frontendDist to ../src for local setup page (no bundled frontend)
- Add placeholder icons for build compatibility (to be replaced in 06-02)
- Add Cargo target/ to .gitignore
- Window config: 1280x800, centered, native decorations, resizable

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/desktop/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "@tessera/desktop",
+  "version": "0.0.1",
+  "private": true,
+  "scripts": {
+    "tauri": "tauri",
+    "dev": "tauri dev",
+    "build": "tauri build"
+  },
+  "dependencies": {
+    "@tauri-apps/api": "^2.11.1",
+    "@tauri-apps/plugin-store": "^2.4.3"
+  },
+  "devDependencies": {
+    "@tauri-apps/cli": "^2.11.3"
+  }
+}