Initial implementation of Claude desktop app (Tauri v2)

Standalone native desktop app wrapping claude.ai with:
- Direct webview navigation to claude.ai (not iframe)
- System tray with close-to-tray behavior
- Native notification bridge (JS overrides browser Notification API)
- Navigation filter allowing only Claude, Anthropic, and OAuth domains
- External links open in system browser
- Session persistence via WebKitGTK cookies/localStorage
- Builds .deb and AppImage bundles

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

src-tauri/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "claude-app"
+version = "1.0.0"
+description = "Claude desktop app"
+edition = "2021"
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[dependencies]
+tauri = { version = "2", features = ["tray-icon", "image-png"] }
+tauri-plugin-notification = "2"
+tauri-plugin-opener = "2"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+url = "2"
+
+[features]
+default = ["custom-protocol"]
+custom-protocol = ["tauri/custom-protocol"]