fix: correct misleading Code node documentation based on real-world testing

Critical fixes based on Claude Desktop feedback:

1. Fixed crypto documentation: require('crypto') IS available despite editor warnings
   - Added clear examples of crypto usage
   - Updated validation to guide correct require() usage

2. Clarified $helpers vs standalone functions
   - $getWorkflowStaticData() is standalone, NOT $helpers.getWorkflowStaticData()
   - Added validation to catch incorrect usage (prevents '$helpers is not defined' errors)
   - Enhanced examples showing proper $helpers availability checks

3. Fixed JMESPath numeric literal documentation
   - n8n requires backticks around numbers in filters: [?age >= `18`]
   - Added multiple examples and validation to detect missing backticks
   - Prevents 'JMESPath syntax error' that Claude Desktop encountered

4. Fixed webhook data access gotcha
   - Webhook payload is at items[0].json.body, NOT items[0].json
   - Added dedicated 'Webhook Data Access' section with clear examples
   - Created process_webhook_data task template
   - Added validation to detect incorrect webhook data access patterns

All fixes based on production workflows TaNqYoZNNeHC4Hne and JZ9urD7PNClDZ1bm

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

Co-Authored-By: Claude <noreply@anthropic.com>

scripts/test-helpers-validation.ts

@@ -0,0 +1,93 @@
+#!/usr/bin/env npx tsx
+
+import { EnhancedConfigValidator } from '../src/services/enhanced-config-validator.js';
+
+console.log('🧪 Testing $helpers Validation\n');
+
+const testCases = [
+  {
+    name: 'Incorrect $helpers.getWorkflowStaticData',
+    config: {
+      language: 'javaScript',
+      jsCode: `const data = $helpers.getWorkflowStaticData('global');
+data.counter = 1;
+return [{json: {counter: data.counter}}];`
+    }
+  },
+  {
+    name: 'Correct $getWorkflowStaticData',
+    config: {
+      language: 'javaScript',
+      jsCode: `const data = $getWorkflowStaticData('global');
+data.counter = 1;
+return [{json: {counter: data.counter}}];`
+    }
+  },
+  {
+    name: '$helpers without check',
+    config: {
+      language: 'javaScript',
+      jsCode: `const response = await $helpers.httpRequest({
+  method: 'GET',
+  url: 'https://api.example.com'
+});
+return [{json: response}];`
+    }
+  },
+  {
+    name: '$helpers with proper check',
+    config: {
+      language: 'javaScript',
+      jsCode: `if (typeof $helpers !== 'undefined' && $helpers.httpRequest) {
+  const response = await $helpers.httpRequest({
+    method: 'GET',
+    url: 'https://api.example.com'
+  });
+  return [{json: response}];
+}
+return [{json: {error: 'HTTP not available'}}];`
+    }
+  },
+  {
+    name: 'Crypto without require',
+    config: {
+      language: 'javaScript',
+      jsCode: `const token = crypto.randomBytes(32).toString('hex');
+return [{json: {token}}];`
+    }
+  },
+  {
+    name: 'Crypto with require',
+    config: {
+      language: 'javaScript',
+      jsCode: `const crypto = require('crypto');
+const token = crypto.randomBytes(32).toString('hex');
+return [{json: {token}}];`
+    }
+  }
+];
+
+for (const test of testCases) {
+  console.log(`Test: ${test.name}`);
+  const result = EnhancedConfigValidator.validateWithMode(
+    'nodes-base.code',
+    test.config,
+    [
+      { name: 'language', type: 'options', options: ['javaScript', 'python'] },
+      { name: 'jsCode', type: 'string' }
+    ],
+    'operation',
+    'ai-friendly'
+  );
+  
+  console.log(`  Valid: ${result.valid}`);
+  if (result.errors.length > 0) {
+    console.log(`  Errors: ${result.errors.map(e => e.message).join(', ')}`);
+  }
+  if (result.warnings.length > 0) {
+    console.log(`  Warnings: ${result.warnings.map(w => w.message).join(', ')}`);
+  }
+  console.log();
+}
+
+console.log('✅ $helpers validation tests completed!');