feat: Enhance diff utilities and tests for configuration changes

- Updated `diff_utils.go` to improve variable naming and output formatting for configuration changes, including renaming version fields for clarity.
- Added initialization of global variables in `diff_test.go` to ensure proper test setup.
- Introduced a utility function to capture stdout during tests, enhancing output validation in `diff_versions_test.go`.
- Updated test cases to reflect changes in output formatting, ensuring consistency in configuration change summaries.

Author: a-spiker

cmd/diff_test.go

@@ -201,6 +201,10 @@ func TestRunServerDiff(t *testing.T) {
 }
 
 func TestDiffFlatMaps(t *testing.T) {
+	if err := InitializeGlobals(); err != nil {
+		t.Fatalf("Failed to initialize globals for testing: %v", err)
+	}
+
 	testCases := []struct {
 		name     string
 		m1       map[string]any