fix: Change let to const for variables that are never reassigned

Fix ESLint errors in error handling code:
- errorMessage: let -> const
- suggestions: let -> const

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

Co-Authored-By: Claude <[email protected]>

Author: facundofarias

src/mcp-server.ts

@@ -146,8 +146,8 @@ export function createMCPServer(
       log.error(`Error executing tool ${name}:`, error);
 
       // Build helpful error message with context
-      let errorMessage = (error as Error).message;
-      let suggestions: string[] = [];
+      const errorMessage = (error as Error).message;
+      const suggestions: string[] = [];
 
       // Add context-specific suggestions based on error type
       if (error instanceof Error) {