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/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "frontend",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview",
+    "check": "svelte-check --tsconfig ./tsconfig.app.json && tsc -p tsconfig.node.json"
+  },
+  "devDependencies": {
+    "@sveltejs/vite-plugin-svelte": "^7.0.0",
+    "@tsconfig/svelte": "^5.0.8",
+    "@types/node": "^24.12.0",
+    "svelte": "^5.53.12",
+    "svelte-check": "^4.4.5",
+    "typescript": "~5.9.3",
+    "vite": "^8.0.1"
+  },
+  "dependencies": {
+    "@xyflow/svelte": "^1.5.2"
+  }
+}