feat: Electrobun Svelte+WGPU prototype (Dawn GPU confirmed on Linux)

- Svelte 5 frontend with Catppuccin Mocha theme, 2 project cards
- Electrobun v1.16.0 with bundleWGPU: true (Dawn on Linux x64)
- WebKitGTK webview + WGPU surface coexistence confirmed
- CPU: 6.5% idle (CSS animation + WebKitGTK overhead)
- Port 9760 for dev server (project convention)

ui-electrobun/src/mainview/main.ts

@@ -0,0 +1,9 @@
+import "./app.css";
+import App from "./App.svelte";
+import { mount } from "svelte";
+
+const app = mount(App, {
+	target: document.getElementById("app")!,
+});
+
+export default app;