fix: resolve CI failures — Node 20+, exclude scanner-worker from build

- Update GitHub Actions workflows to Node 20/22 (ESLint 10 requires Node 20+)
- Exclude scanner-worker/ from frontend tsconfig and .dockerignore
- Update engines to require Node >= 20

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

package.json

@@ -28,6 +28,6 @@
     "husky": "^9.1.0"
   },
   "engines": {
-    "node": ">=18.0.0"
+    "node": ">=20.0.0"
   }
 }