Initial commit: pwweb - PipeWire WebUI

C++ backend with SSE streaming (reuses qpwgraph PipeWire callbacks).
Svelte frontend with custom SVG canvas for port-level connections.

Features:
- Live PipeWire graph via SSE
- Drag output->input port to connect
- Double-click or select+Delete to disconnect
- Node positions saved to localStorage
- Pan (drag bg) and zoom (scroll)
- Port type coloring (audio=green, midi=red, video=blue)

frontend/vite.config.ts

@@ -0,0 +1,20 @@
+import { defineConfig } from 'vite'
+import { svelte } from '@sveltejs/vite-plugin-svelte'
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [svelte()],
+  server: {
+    port: 5173,
+    proxy: {
+      '/api': {
+        target: 'http://localhost:9876',
+        changeOrigin: true,
+      },
+      '/events': {
+        target: 'http://localhost:9876',
+        changeOrigin: true,
+      },
+    },
+  },
+})