fix(@angular/build): preserve names in esbuild for improved debugging in dev mode

This commit introduces the `keepNames` option in esbuild configurations for both application code bundling and Vite utility functions.

By setting `keepNames` to `true` (or conditionally based on optimization settings), function and variable names are preserved during the build process. This significantly improves the debugging experience in **development mode** by ensuring that original names are retained in compiled output, leading to more readable stack traces and easier identification of code sections during development.

Author: alan-agius4

packages/angular/build/src/tools/esbuild/application-code-bundle.ts

@@ -607,6 +607,8 @@ function getEsBuildCommonOptions(options: NormalizedApplicationBuildOptions): Bu
     }
   }
 
+  const minifyIdentifiers = optimizationOptions.scripts && allowMangle;
+
   return {
     absWorkingDir: workspaceRoot,
     format: 'esm',
@@ -618,7 +620,8 @@ function getEsBuildCommonOptions(options: NormalizedApplicationBuildOptions): Bu
     metafile: true,
     legalComments: options.extractLicenses ? 'none' : 'eof',
     logLevel: options.verbose && !jsonLogs ? 'debug' : 'silent',
-    minifyIdentifiers: optimizationOptions.scripts && allowMangle,
+    keepNames: !minifyIdentifiers,
+    minifyIdentifiers,
     minifySyntax: optimizationOptions.scripts,
     minifyWhitespace: optimizationOptions.scripts,
     pure: ['forwardRef'],

packages/angular/build/src/tools/vite/utils.ts

@@ -98,6 +98,7 @@ export function getDepOptimizationConfig({
     esbuildOptions: {
       // Set esbuild supported targets.
       target,
+      keepNames: true,
       supported: getFeatureSupport(target, zoneless),
       plugins,
       loader,