chore: update n8n to 2.4.4 (#543)

* 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>

* fix: update n8n-workflow version in Dockerfile for icon type support

The Docker build was using n8n-workflow@^1.96.0 which doesn't have the new
'icon' NodePropertyType. Updated to n8n-workflow@^2.4.2 to match the project's
package.json version.

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>

* fix: update comments to reflect 23 NodePropertyTypes

- Updated test comment from '22 standard types' to '23 standard types'
- Updated header comment from n8n-workflow v1.120.3 to v2.4.2

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>

---------

Co-authored-by: Claude <noreply@anthropic.com>

tests/unit/services/type-structure-service.test.ts

@@ -58,9 +58,9 @@ describe('TypeStructureService', () => {
 	});
 
 	describe('getAllStructures', () => {
-		it('should return all 22 type structures', () => {
+		it('should return all 23 type structures', () => {
 			const structures = TypeStructureService.getAllStructures();
-			expect(Object.keys(structures)).toHaveLength(22);
+			expect(Object.keys(structures)).toHaveLength(23);
 		});
 
 		it('should return a copy not a reference', () => {