feat: Add Angular, HTML, and SCSS / Sass language servers (#1439)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Pavlo Basanets <Pavlo_Basanets@epam.com>

test/resources/repos/angular/test_repo/angular.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
+  "version": 1,
+  "newProjectRoot": "projects",
+  "projects": {
+    "serena-test-app": {
+      "projectType": "application",
+      "root": "",
+      "sourceRoot": "src",
+      "prefix": "app",
+      "architect": {
+        "build": {
+          "builder": "@angular-devkit/build-angular:application",
+          "options": {
+            "outputPath": "dist/serena-test-app",
+            "index": "src/index.html",
+            "browser": "src/main.ts",
+            "tsConfig": "tsconfig.app.json"
+          }
+        }
+      }
+    }
+  }
+}