FIX: Smart parser selection to support decorators when LWC base config disabled

Problem:
When users set 'disable_lwc_base_config: true', JavaScript files containing
LWC decorators (@api, @track, @wire) failed to parse with error:
'Unexpected character @'

Root Cause:
- createJavascriptConfigArray() used Espree parser (ESLint default)
- Espree does not support decorators, only Babel does
- Users disable LWC base config to avoid LWC-specific rules, but still have
  LWC files with decorators that need to be parsed

Solution:
Implement smart parser selection based on file extensions:
- If .js extension is included → Use Babel parser (supports decorators)
- If only .jsx, .mjs, .cjs → Use Espree parser (faster, no decorators needed)

Benefits:
- Fixes decorator parsing when disable_lwc_base_config: true
- Preserves Espree performance optimization for React-only projects
- Both parsers remain useful (no dead code)
- Automatic detection (no new config needed)
- Backwards compatible

Test Cases:
- .js files with LWC decorators: Works (Babel)
- .jsx files with React JSX: Works (Espree for performance)
- Mixed .js + .jsx: Works (Babel handles both)

Author: aruntyagiTutu

packages/code-analyzer-eslint-engine/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@salesforce/code-analyzer-eslint-engine",
   "description": "Plugin package that adds 'eslint' as an engine into Salesforce Code Analyzer",
-  "version": "0.40.0",
+  "version": "0.41.0-SNAPSHOT",
   "author": "The Salesforce Code Analyzer Team",
   "license": "BSD-3-Clause",
   "homepage": "https://developer.salesforce.com/docs/platform/salesforce-code-analyzer/overview",

packages/code-analyzer-eslint-engine/src/base-config.ts

@@ -148,17 +148,39 @@ export class BaseConfigFactory {
     }
 
     private createJavascriptConfigArray(): Linter.Config[] {
-        return [{
-            ... eslintJs.configs.all,
-            files: this.engineConfig.file_extensions.javascript.map(ext => `**/*${ext}`),
-            languageOptions: {
-                parserOptions: {
-                    ecmaFeatures: {
-                        jsx: true  // Enable JSX parsing for React/JSX files
+        // Smart parser selection based on file extensions:
+        // - .js files may contain LWC decorators (@api, @track, @wire) → need Babel
+        // - .jsx, .mjs, .cjs are typically React or modules without decorators → can use Espree (faster)
+        const hasJsExtension = this.engineConfig.file_extensions.javascript.includes('.js');
+
+        if (hasJsExtension) {
+            // .js files might have LWC decorators - use Babel parser with decorator support
+            const lwcConfig = validateAndGetRawLwcConfigArray()[0];
+            const babelParser = lwcConfig.languageOptions?.parser;
+            const babelParserOptions = lwcConfig.languageOptions?.parserOptions;
+
+            return [{
+                ... eslintJs.configs.all,
+                files: this.engineConfig.file_extensions.javascript.map(ext => `**/*${ext}`),
+                languageOptions: {
+                    parser: babelParser,
+                    parserOptions: babelParserOptions
+                }
+            }];
+        } else {
+            // Only .jsx, .mjs, .cjs (no .js) - use Espree for better performance
+            return [{
+                ... eslintJs.configs.all,
+                files: this.engineConfig.file_extensions.javascript.map(ext => `**/*${ext}`),
+                languageOptions: {
+                    parserOptions: {
+                        ecmaFeatures: {
+                            jsx: true  // Enable JSX parsing for React/JSX files
+                        }
                     }
                 }
-            }
-        }];
+            }];
+        }
     }
 
     private createSldsHTMLConfigArray(): Linter.Config[] {