Add webapp subproject (Vite + TypeScript + Web Components)

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

webapp/tsconfig.json

@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "target": "ESNext",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "lib": ["ES2022", "DOM"],
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "useDefineForClassFields": true,
+    "outDir": "dist",
+    "rootDir": "src"
+  },
+  "include": ["src"]
+}