fix: correct error message expectations in resource tests

Fixes test failures by updating error message expectations to match actual
error message flow from list_simsLogic function:

- Command execution failures return ''Failed to list simulators: ...'' directly
- Spawn errors get caught by resource handler and prefixed with ''Error retrieving simulator data:''

The resource handler already supports proper dependency injection for testing.

Co-authored-by: Cameron Cooke <cameroncooke@users.noreply.github.com>

Author: claude[bot]

src/core/__tests__/resources.test.ts

@@ -164,7 +164,8 @@ describe('resources', () => {
 
       expect(result.contents).toHaveLength(1);
       expect(result.contents[0].type).toBe('text');
-      expect(result.contents[0].text).toContain('Error retrieving simulator data');
+      expect(result.contents[0].text).toContain('Failed to list simulators');
+      expect(result.contents[0].text).toContain('Command failed');
     });
 
     it('should handle JSON parsing errors', async () => {