perf: optimize workflow tool responses for token efficiency (v2.29.0) (#479)

* perf: optimize workflow tool responses for token efficiency (v2.29.0)

Reduce response sizes by 75-90% for 4 workflow management tools:

- n8n_update_partial_workflow: Returns {id, name, active, operationsApplied}
- n8n_create_workflow: Returns {id, name, active, nodeCount}
- n8n_update_full_workflow: Returns {id, name, active, nodeCount}
- n8n_delete_workflow: Returns {id, name, deleted: true}

AI agents can use n8n_get_workflow with mode 'structure' if they need
to verify the current workflow state after operations.

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 tests and add nodeCount to partial update response

- Fix handleCreateWorkflow test to expect minimal response
- Fix handleDeleteWorkflow test to expect minimal response
- Add nodeCount to n8n_update_partial_workflow response for consistency
- Update documentation and CHANGELOG

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 handlers-workflow-diff tests for minimal response

Update 3 more tests that expected full workflow in response:
- should apply diff operations successfully
- should activate workflow after successful update
- should deactivate workflow after successful update

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

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

* fix: update integration tests to use minimal response format

Integration tests now verify minimal response format and use
client.getWorkflow() to fetch actual workflow state for verification.

Conceived by Romuald Czlonkowski - www.aiadvisors.pl/en

* fix: update create/update workflow integration tests for minimal response

Integration tests now verify minimal response and use client.getWorkflow()
to fetch actual workflow state for detailed verification.

Conceived by Romuald Czlonkowski - www.aiadvisors.pl/en

* fix: add type assertions to fix TypeScript errors in tests

Conceived by Romuald Czlonkowski - www.aiadvisors.pl/en

---------

Co-authored-by: Romuald Członkowski <romualdczlonkowski@MacBook-Pro-Romuald.local>
Co-authored-by: Claude <noreply@anthropic.com>

tests/unit/mcp/handlers-workflow-diff.test.ts

@@ -150,13 +150,15 @@ describe('handlers-workflow-diff', () => {
 
       expect(result).toEqual({
         success: true,
-        data: updatedWorkflow,
-        message: 'Workflow "Test Workflow" updated successfully. Applied 1 operations.',
-        details: {
-          operationsApplied: 1,
-          workflowId: 'test-workflow-id',
-          workflowName: 'Test Workflow',
+        data: {
+          id: 'test-workflow-id',
+          name: 'Test Workflow',
           active: true,
+          nodeCount: 3,
+          operationsApplied: 1,
+        },
+        message: 'Workflow "Test Workflow" updated successfully. Applied 1 operations. Use n8n_get_workflow with mode \'structure\' to verify current state.',
+        details: {
           applied: [0],
           failed: [],
           errors: [],
@@ -660,9 +662,15 @@ describe('handlers-workflow-diff', () => {
         }, mockRepository);
 
         expect(result.success).toBe(true);
-        expect(result.data).toEqual(activatedWorkflow);
+        expect(result.data).toEqual({
+          id: 'test-workflow-id',
+          name: 'Test Workflow',
+          active: true,
+          nodeCount: 2,
+          operationsApplied: 1,
+        });
         expect(result.message).toContain('Workflow activated');
-        expect(result.details?.active).toBe(true);
+        expect((result.data as any).active).toBe(true);
         expect(mockApiClient.activateWorkflow).toHaveBeenCalledWith('test-workflow-id');
       });
 
@@ -689,9 +697,15 @@ describe('handlers-workflow-diff', () => {
         }, mockRepository);
 
         expect(result.success).toBe(true);
-        expect(result.data).toEqual(deactivatedWorkflow);
+        expect(result.data).toEqual({
+          id: 'test-workflow-id',
+          name: 'Test Workflow',
+          active: false,
+          nodeCount: 2,
+          operationsApplied: 1,
+        });
         expect(result.message).toContain('Workflow deactivated');
-        expect(result.details?.active).toBe(false);
+        expect((result.data as any).active).toBe(false);
         expect(mockApiClient.deactivateWorkflow).toHaveBeenCalledWith('test-workflow-id');
       });