feat: update tsconfig for Angular 21 best practices - add stricter compiler options, use Bundler moduleResolution, and preserve module

Co-authored-by: Lipata <[email protected]>

Author: Copilot

packages/igx-templates/igx-ts-legacy/projects/_base/files/tsconfig.json

@@ -5,16 +5,21 @@
     "baseUrl": "./",
     "outDir": "./dist/out-tsc",
     "forceConsistentCasingInFileNames": true,
+    "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
     "skipLibCheck": true,
+    "isolatedModules": true,
     "strict": true,
     "sourceMap": true,
     "declaration": false,
     "downlevelIteration": true,
     "experimentalDecorators": true,
-    "moduleResolution": "node",
+    "moduleResolution": "Bundler",
     "importHelpers": true,
     "target": "ES2022",
-    "module": "ES2022",
+    "module": "preserve",
     "useDefineForClassFields": false,
     "lib": [
       "ES2022",

packages/igx-templates/igx-ts/projects/_base/files/tsconfig.json

@@ -9,14 +9,15 @@
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,
     "skipLibCheck": true,
+    "isolatedModules": true,
     "esModuleInterop": true,
     "sourceMap": true,
     "declaration": false,
     "experimentalDecorators": true,
     "moduleResolution": "Bundler",
     "importHelpers": true,
     "target": "ES2022",
-    "module": "ES2022",
+    "module": "preserve",
     "useDefineForClassFields": false,
     "lib": [
       "ES2022",