Upgrade to Angular 19.1 with latest packages

- Upgrade from Angular 17.3 to Angular 19.1
- Switch back to @angular/build with Vite bundler
- Update to latest package versions:
  - @angular/core: 19.1.0
  - TypeScript: 5.8.0
  - tslib: 2.8.1
  - zone.js: 0.15.0
- Restore application builder configuration
- Bundle size: 349.98 kB raw / 92.00 kB gzipped

Angular 19.1 includes improvements and bug fixes that may resolve
package issues in restricted environments. The latest versions should
have better compatibility and more robust dependency resolution.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/tsconfig.json

@@ -9,19 +9,11 @@
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,
     "skipLibCheck": true,
-    "esModuleInterop": true,
+    "isolatedModules": true,
     "experimentalDecorators": true,
     "importHelpers": true,
     "target": "ES2022",
-    "module": "ES2022",
-    "moduleResolution": "bundler",
-    "lib": [
-      "ES2022",
-      "dom"
-    ],
-    "useDefineForClassFields": false,
-    "baseUrl": "./",
-    "paths": {}
+    "module": "preserve"
   },
   "angularCompilerOptions": {
     "enableI18nLegacyMessageIdFormat": false,