fix: resolve LRU cache test failures and TypeScript linting errors

- Fix module resolution issues in LRU cache tests by using proper vi.mock() with importActual
- Fix mock call count expectations by using valid API keys instead of empty strings
- Add explicit types to test objects to resolve TypeScript linting errors
- Change logger mock types to 'any' to avoid complex type issues
- Add vi.clearAllMocks() for proper test isolation

All tests now pass and TypeScript linting succeeds without errors.

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

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

tests/unit/flexible-instance-security-advanced.test.ts

@@ -21,7 +21,7 @@ vi.mock('../../src/utils/logger');
 describe('Advanced Security and Error Handling Tests', () => {
   let mockN8nApiClient: Mock;
   let mockGetN8nApiConfigFromContext: Mock;
-  let mockLogger: Mock;
+  let mockLogger: any; // Logger mock has complex type
 
   beforeEach(() => {
     vi.resetAllMocks();

tests/unit/mcp/handlers-n8n-manager-simple.test.ts

@@ -187,7 +187,7 @@ describe('handlers-n8n-manager Simple Coverage Tests', () => {
 
   describe('Array and Object Handling', () => {
     it('should handle undefined array lengths', () => {
-      const workflowData = {
+      const workflowData: { nodes?: any[] } = {
         nodes: undefined
       };
 
@@ -283,7 +283,7 @@ describe('handlers-n8n-manager Simple Coverage Tests', () => {
     });
 
     it('should handle missing dependencies', () => {
-      const packageJson = {};
+      const packageJson: { dependencies?: { n8n?: string } } = {};
 
       const supportedVersion = packageJson.dependencies?.n8n?.replace(/[^0-9.]/g, '') || '';
 

tests/unit/mcp/lru-cache-behavior.test.ts

@@ -28,7 +28,7 @@ vi.mock('../../../src/types/instance-context', async () => {
 describe('LRU Cache Behavior Tests', () => {
   let mockN8nApiClient: Mock;
   let mockGetN8nApiConfigFromContext: Mock;
-  let mockLogger: Mock;
+  let mockLogger: any; // Logger mock has complex type
   let mockValidateInstanceContext: Mock;
 
   beforeEach(() => {