feat(tests): implement Phase 2 integration testing - workflow creation tests

Implements comprehensive workflow creation tests against real n8n instance
with 15 test scenarios covering P0 bugs, base nodes, advanced features,
error scenarios, and edge cases.

Key Changes:
- Added 15 workflow creation test scenarios in create-workflow.test.ts
- Fixed critical MSW interference with real API calls
- Fixed environment loading priority (.env before test defaults)
- Implemented multi-level cleanup with webhook workflow preservation
- Migrated from webhook IDs to webhook URLs configuration
- Added TypeScript type safety fixes (26 errors resolved)
- Updated test names to reflect actual n8n API behavior

Bug Fixes:
- Removed MSW from integration test setup (was blocking real API calls)
- Fixed .env loading order to preserve real credentials over test defaults
- Added type guards for undefined workflow IDs
- Fixed position arrays to use proper tuple types [number, number]
- Added literal types for executionOrder and settings values

Test Coverage:
- P0: Critical bug verification (FULL vs SHORT node type format)
- P1: Base n8n nodes (webhook, HTTP, langchain, multi-node)
- P2: Advanced features (connections, settings, expressions, error handling)
- Error scenarios (documents actual n8n API validation behavior)
- Edge cases (minimal workflows, empty connections, no settings)

Technical Improvements:
- Cleanup strategy preserves pre-activated webhook workflows
- Single webhook URL accepts all HTTP methods (GET, POST, PUT, DELETE)
- Environment-aware credential loading with validation
- Comprehensive test context for resource tracking

All 15 tests passing ✅
TypeScript: 0 errors ✅

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

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

vitest.config.integration.ts

@@ -5,8 +5,9 @@ export default mergeConfig(
   baseConfig,
   defineConfig({
     test: {
-      // Include both global setup and integration-specific MSW setup
-      setupFiles: ['./tests/setup/global-setup.ts', './tests/integration/setup/integration-setup.ts'],
+      // Include global setup, but NOT integration-setup.ts for n8n-api tests
+      // (they need real network requests, not MSW mocks)
+      setupFiles: ['./tests/setup/global-setup.ts'],
       // Only include integration tests
       include: ['tests/integration/**/*.test.ts'],
       // Integration tests might need more time