fix: resolve TypeScript compilation errors in integration tests

Fixed multiple TypeScript errors preventing clean build:
- Fixed import paths for ValidationResponse type (5 test files)
- Fixed validateBasicLLMChain function signature (removed extra workflow parameter)
- Enhanced ValidationResponse interface to include missing properties:
  - Added code, nodeName fields to errors/warnings
  - Added info array for informational messages
  - Added suggestions array
- Fixed type assertion in mergeConnections helper
- Fixed implicit any type in chat-trigger-validation test

All tests now compile cleanly with no TypeScript errors.

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

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

tests/integration/n8n-api/types/mcp-responses.ts

@@ -24,14 +24,32 @@ export interface ValidationResponse {
   };
   errors?: Array<{
     node: string;
+    nodeName?: string;
     message: string;
-    details?: unknown;
+    details?: {
+      code?: string;
+      [key: string]: unknown;
+    };
+    code?: string;
   }>;
   warnings?: Array<{
     node: string;
+    nodeName?: string;
     message: string;
+    details?: {
+      code?: string;
+      [key: string]: unknown;
+    };
+    code?: string;
+  }>;
+  info?: Array<{
+    node: string;
+    nodeName?: string;
+    message: string;
+    severity?: string;
     details?: unknown;
   }>;
+  suggestions?: string[];
 }
 
 /**