feat(tests): implement Phase 3 integration tests - workflow retrieval

Phase 3: Workflow Retrieval Tests (11 tests, all passing)

## Test Files Created:
- tests/integration/n8n-api/workflows/get-workflow.test.ts (3 scenarios)
- tests/integration/n8n-api/workflows/get-workflow-details.test.ts (4 scenarios)
- tests/integration/n8n-api/workflows/get-workflow-structure.test.ts (2 scenarios)
- tests/integration/n8n-api/workflows/get-workflow-minimal.test.ts (2 scenarios)
- tests/integration/n8n-api/utils/mcp-context.ts (helper for MCP context)

## Key Features:
- All tests use MCP handlers instead of direct API client calls
- Tests verify handleGetWorkflow, handleGetWorkflowDetails, handleGetWorkflowStructure, handleGetWorkflowMinimal
- Proper error handling tests for invalid/malformed IDs
- Version history tracking verification
- Execution statistics validation
- Flexible assertions to document actual n8n API behavior

## API Behavior Discoveries:
- Tags may not be returned in GET requests even when set during creation
- typeVersion field may be undefined in some API responses
- handleGetWorkflowDetails wraps response in {workflow, executionStats, hasWebhookTrigger, webhookPath}
- Minimal workflow view may not include tags or node data

All 11 tests passing locally.

tests/integration/n8n-api/workflows/get-workflow.test.ts

@@ -0,0 +1,113 @@
+/**
+ * Integration Tests: handleGetWorkflow
+ *
+ * Tests workflow retrieval against a real n8n instance.
+ * Covers successful retrieval and error handling.
+ */
+
+import { describe, it, expect, beforeEach, afterEach, afterAll } from 'vitest';
+import { createTestContext, TestContext, createTestWorkflowName } from '../utils/test-context';
+import { getTestN8nClient } from '../utils/n8n-client';
+import { N8nApiClient } from '../../../../src/services/n8n-api-client';
+import { SIMPLE_WEBHOOK_WORKFLOW } from '../utils/fixtures';
+import { cleanupOrphanedWorkflows } from '../utils/cleanup-helpers';
+import { createMcpContext } from '../utils/mcp-context';
+import { InstanceContext } from '../../../../src/types/instance-context';
+import { handleGetWorkflow } from '../../../../src/mcp/handlers-n8n-manager';
+
+describe('Integration: handleGetWorkflow', () => {
+  let context: TestContext;
+  let client: N8nApiClient;
+  let mcpContext: InstanceContext;
+
+  beforeEach(() => {
+    context = createTestContext();
+    client = getTestN8nClient();
+    mcpContext = createMcpContext();
+  });
+
+  afterEach(async () => {
+    await context.cleanup();
+  });
+
+  afterAll(async () => {
+    if (!process.env.CI) {
+      await cleanupOrphanedWorkflows();
+    }
+  });
+
+  // ======================================================================
+  // Successful Retrieval
+  // ======================================================================
+
+  describe('Successful Retrieval', () => {
+    it('should retrieve complete workflow data', async () => {
+      // Create a workflow first
+      const workflow = {
+        ...SIMPLE_WEBHOOK_WORKFLOW,
+        name: createTestWorkflowName('Get Workflow - Complete Data'),
+        tags: [{ name: 'mcp-integration-test' }]
+      };
+
+      const created = await client.createWorkflow(workflow);
+      expect(created).toBeDefined();
+      expect(created.id).toBeTruthy();
+
+      if (!created.id) throw new Error('Workflow ID is missing');
+      context.trackWorkflow(created.id);
+
+      // Retrieve the workflow using MCP handler
+      const response = await handleGetWorkflow({ id: created.id }, mcpContext);
+
+      // Verify MCP response structure
+      expect(response.success).toBe(true);
+      expect(response.data).toBeDefined();
+
+      const retrieved = response.data;
+
+      // Verify all expected fields are present
+      expect(retrieved).toBeDefined();
+      expect(retrieved.id).toBe(created.id);
+      expect(retrieved.name).toBe(workflow.name);
+      expect(retrieved.nodes).toBeDefined();
+      expect(retrieved.nodes).toHaveLength(workflow.nodes.length);
+      expect(retrieved.connections).toBeDefined();
+      expect(retrieved.active).toBeDefined();
+      expect(retrieved.createdAt).toBeDefined();
+      expect(retrieved.updatedAt).toBeDefined();
+
+      // Verify node data integrity
+      const retrievedNode = retrieved.nodes[0];
+      const originalNode = workflow.nodes[0];
+      expect(retrievedNode.name).toBe(originalNode.name);
+      expect(retrievedNode.type).toBe(originalNode.type);
+      expect(retrievedNode.parameters).toBeDefined();
+    });
+  });
+
+  // ======================================================================
+  // Error Handling
+  // ======================================================================
+
+  describe('Error Handling', () => {
+    it('should return error for non-existent workflow (invalid ID)', async () => {
+      const invalidId = '99999999';
+
+      const response = await handleGetWorkflow({ id: invalidId }, mcpContext);
+
+      // MCP handlers return success: false on error
+      expect(response.success).toBe(false);
+      expect(response.error).toBeDefined();
+    });
+
+    it('should return error for malformed workflow ID', async () => {
+      const malformedId = 'not-a-valid-id-format';
+
+      const response = await handleGetWorkflow({ id: malformedId }, mcpContext);
+
+      // MCP handlers return success: false on error
+      expect(response.success).toBe(false);
+      expect(response.error).toBeDefined();
+    });
+  });
+});