Add eslint/tsc to postcss custom plugins

Author: NuckChorris

.eslintrc.js

@@ -60,7 +60,7 @@ module.exports = {
       },
     },
     {
-      files: ['.eslintrc.js', '*.config.{js,ts}'],
+      files: ['.eslintrc.js', '*.config.{js,ts}', 'postcss/*.js'],
       parserOptions: {
         sourceType: 'script',
         ecmaVersion: 2015,
@@ -69,6 +69,9 @@ module.exports = {
         browser: false,
         node: true,
       },
+      rules: {
+        '@typescript-eslint/no-var-requires': 'off',
+      },
     },
   ],
 };

tsconfig.node.json

@@ -3,7 +3,14 @@
     "composite": true,
     "module": "esnext",
     "moduleResolution": "node",
+    "allowJs": true,
+    "checkJs": true,
     "allowSyntheticDefaultImports": true
   },
-  "include": ["vite.config.ts", "rollup/imageMetadataPlugin.ts"]
+  "include": [
+    "vite.config.ts",
+    "rollup/imageMetadataPlugin.ts",
+    "postcss/resolveLocalCustomProperties.js",
+    "postcss/validateThemeVariables.js"
+  ]
 }