Fix command launcher in event preview (#42)

* fix(CommandLauncher): redirect to dashboard when executing commands from preview routes

NIP-19 preview routes (/nevent..., /npub..., etc.) don't render the
window system, so commands executed there appeared to do nothing.
Now detects preview routes and navigates to the dashboard before
creating the window, so the command actually takes effect.

* fix(test): add WebSocket polyfill for Node.js test environment

nostr-tools relay code requires WebSocket which isn't available in
Node.js by default. Adding the ws package polyfill prevents
"ReferenceError: WebSocket is not defined" errors in tests.

* fix(test): add @types/ws and fix type cast for WebSocket polyfill

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Co-authored-by: Claude <noreply@anthropic.com>

package.json

@@ -81,6 +81,7 @@
     "@types/react-dom": "^19.2.3",
     "@types/shell-quote": "^1.7.5",
     "@types/uuid": "^10.0.0",
+    "@types/ws": "^8.18.1",
     "@vitejs/plugin-react": "^4.3.4",
     "@vitest/ui": "^4.0.15",
     "autoprefixer": "^10.4.20",