feat: Add ESLint complexity and code size rules

Author: killev

workers/main/eslint.config.mjs

@@ -62,6 +62,21 @@ export default [
       ],
       'simple-import-sort/imports': 'error',
       'simple-import-sort/exports': 'error',
+      
+      // Code complexity and size rules
+      'max-depth': ['error', 4],
+      'max-lines': ['error', 300],
+      'max-nested-callbacks': ['error', 3],
+      'max-params': ['error', 5],
+      'max-statements': ['error', 50],
+      'complexity': ['error', 15],
+    },
+  },
+  // Override for test files to allow more nested callbacks
+  {
+    files: ['**/*.test.ts', '**/*.test.js'],
+    rules: {
+      'max-nested-callbacks': ['error', 4],
     },
   },
 ];