feat(web): scaffold Vite + React + TS SPA with Vitest

Bootstraps the web/ SPA: Vite 6 + React 19 + TypeScript 5.8, Vitest
with jsdom, @testing-library/react, and a green smoke test asserting
the App renders its Collection heading.

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

web/tsconfig.app.json

@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
+    "target": "ES2020",
+    "useDefineForClassFields": true,
+    "lib": ["ES2020", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "skipLibCheck": true,
+
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "isolatedModules": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+    "jsx": "react-jsx",
+
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedSideEffectImports": true,
+    "types": ["vitest/globals"]
+  },
+  "include": ["src"]
+}