chore: remove deprecated babel and stylelint dependencies (#7659)

* chore: remove deprecated babel and stylelint dependencies

* chore: add .claude directory to .gitignore

* chore: replace deprecated stylelint packages with modern alternative

Replace stylelint-processor-styled-components and stylelint-config-styled-components
with postcss-styled-syntax to lint CSS-in-JS files.

- Install postcss-styled-syntax
- Update .stylelintrc to use postcss-styled-syntax
- Re-enable linting for js,jsx,ts,tsx files in lint:css command
- Disable stylelint rules incompatible with CSS-in-JS syntax

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* chore: remove .claude/settings.local.json from git tracking

---------

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

Author: cmbdurand46

.eslintrc.js

@@ -6,7 +6,13 @@ const packages = fs
   .map(dirent => dirent.name);
 
 module.exports = {
-  parser: 'babel-eslint',
+  parser: '@babel/eslint-parser',
+  parserOptions: {
+    requireConfigFile: false,
+    babelOptions: {
+      presets: ['@babel/preset-react'],
+    },
+  },
   extends: [
     'eslint:recommended',
     'plugin:react/recommended',

.gitignore

@@ -8,6 +8,7 @@ npm-debug.log
 yarn-error.log
 .vscode/
 .idea/
+.claude/
 manifest.yml
 .imdone/
 cypress/videos

.stylelintrc

@@ -1,7 +1,6 @@
 {
-  "processors": ["stylelint-processor-styled-components"],
-  "extends": ["stylelint-config-standard-scss", "stylelint-config-styled-components"],
-  "customSyntax": "postcss-scss",
+  "extends": ["stylelint-config-standard-scss"],
+  "customSyntax": "postcss-styled-syntax",
   "rules": {
     "block-no-empty": null,
     "no-duplicate-selectors": null,
@@ -19,15 +18,21 @@
     "keyframes-name-pattern": null,
     "value-list-comma-newline-after": null,
     "no-descending-specificity": null,
+    "indentation": null,
+    "no-empty-first-line": null,
+    "no-eol-whitespace": null,
+    "no-missing-end-of-source-newline": null,
+    "scss/operator-no-unspaced": null,
+    "scss/operator-no-newline-after": null,
+    "value-keyword-case": null,
+    "function-name-case": null,
+    "function-whitespace-after": null,
+    "selector-max-empty-lines": null,
     "selector-type-no-unknown": [
       true,
       {
         "ignoreTypes": ["$dummyValue"]
       }
-    ],
-    "value-keyword-case": [
-      "lower",
-      { "ignoreKeywords": ["dummyValue"], "camelCaseSvgKeywords": true }
     ]
   },
   "ignoreFiles": ["packages/decap-cms-lib-auth/index.d.ts"]

babel.config.js

@@ -19,19 +19,10 @@ const basePlugins = [
   'babel-plugin-inline-json-import',
 ];
 
-// Legacy transforms for non-ESM builds
-// REVISIT: We probably don't need any of these since we use preset-env
-const legacyPlugins = [
-  'transform-export-extensions',
-  '@babel/plugin-proposal-class-properties',
-  '@babel/plugin-proposal-object-rest-spread',
-  '@babel/plugin-proposal-export-default-from',
-  '@babel/plugin-proposal-nullish-coalescing-operator',
-  '@babel/plugin-proposal-optional-chaining',
-  '@babel/plugin-syntax-dynamic-import',
-];
+// All legacy transforms have been removed as they are now included in @babel/preset-env
+// Features like class properties, optional chaining, nullish coalescing are now standard in modern JS
 
-const defaultPlugins = [...basePlugins, ...(isESM ? [] : legacyPlugins)];
+const defaultPlugins = [...basePlugins];
 
 const svgo = {
   plugins: [