chore: update n8n to 2.4.4 and bump version to 2.33.3

- Updated n8n from 2.2.3 to 2.4.4
- Updated n8n-core from 2.2.2 to 2.4.2
- Updated n8n-workflow from 2.2.2 to 2.4.2
- Updated @n8n/n8n-nodes-langchain from 2.2.2 to 2.4.3
- Added new `icon` NodePropertyType (now 23 types total)
- Rebuilt node database with 803 nodes (541 from n8n-nodes-base, 262 from @n8n/n8n-nodes-langchain)
- Updated README badge with new n8n version
- Updated CHANGELOG with dependency changes

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

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

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

dist/constants/type-structures.js

@@ -545,6 +545,22 @@ exports.TYPE_STRUCTURES = {
             'One-time import feature',
         ],
     },
+    icon: {
+        type: 'primitive',
+        jsType: 'string',
+        description: 'Icon identifier for visual representation',
+        example: 'fa:envelope',
+        examples: ['fa:envelope', 'fa:user', 'fa:cog', 'file:slack.svg'],
+        validation: {
+            allowEmpty: false,
+            allowExpressions: false,
+        },
+        notes: [
+            'References icon by name or file path',
+            'Supports Font Awesome icons (fa:) and file paths (file:)',
+            'Used for visual customization in UI',
+        ],
+    },
 };
 exports.COMPLEX_TYPE_EXAMPLES = {
     collection: {