test: add Phase 4 database integration tests (partial)

- Add comprehensive test utilities for database testing
- Implement connection management tests for in-memory and file databases
- Add transaction tests including nested transactions and savepoints
- Test database lifecycle, error handling, and performance
- Include tests for WAL mode, connection pooling, and constraints

Part of Phase 4: Integration Testing

scripts/test-msw-setup.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+# Test MSW setup for n8n-mcp
+echo "Testing MSW (Mock Service Worker) setup..."
+echo "========================================"
+
+# Build the project first
+echo "Building project..."
+npm run build
+
+# Run the MSW setup test
+echo -e "\nRunning MSW setup verification test..."
+npm test tests/integration/msw-setup.test.ts
+
+# Check if test passed
+if [ $? -eq 0 ]; then
+    echo -e "\n✅ MSW setup is working correctly!"
+    echo "You can now use MSW for mocking n8n API in your integration tests."
+else
+    echo -e "\n❌ MSW setup test failed. Please check the errors above."
+    exit 1
+fi