Fix frontend TypeScript build errors

- Inline tsconfig.base.json settings into frontend/tsconfig.json (same
  Docker context issue as backend — only frontend/ is copied)
- Upgrade @types/react and @types/react-dom to ^19.0.0 to satisfy
  antd 5.20.x which references React.ActionDispatch (React 19 type);
  React 18 runtime is unchanged

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

frontend/tsconfig.json

@@ -1,11 +1,15 @@
 {
-  "extends": "../tsconfig.base.json",
   "compilerOptions": {
     "target": "ES2020",
     "module": "ESNext",
     "lib": ["ES2020", "DOM", "DOM.Iterable"],
     "jsx": "react-jsx",
     "moduleResolution": "bundler",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
     "noUnusedLocals": false,
     "noUnusedParameters": false,
     "noFallthroughCasesInSwitch": true,