build(deps-dev): replace deprecated build-angular with @angular/build

Angular's Webpack-based @angular-devkit/build-angular is deprecated. Depending on @angular/build directly drops webpack-dev-server and http-proxy-middleware, which pulled in the unpatched braces advisory GHSA-vfj7-8cjw-p6xm.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -74,7 +74,7 @@
     "zone.js": "~0.16.2"
   },
   "devDependencies": {
-    "@angular-devkit/build-angular": "^22.2.1",
+    "@angular/build": "^22.2.1",
     "@angular/cli": "^22.2.1",
     "@angular/compiler-cli": "^22.2.1",
     "@types/express": "^5.0.6",