fix(cmd): use Fprintf for efficiency and handle Chdir error in tests

- Replace WriteString + Sprintf with Fprintf in harvestContext for better performance.
- Wrap deferred Chdir in scaffold tests with error logging to avoid silent failures.

cmd/scaffold.go

@@ -165,7 +165,8 @@ func harvestContext(filePath, lang string) string {
 			if len(content) > 2000 {
 				content = content[:2000]
 			}
-			sb.WriteString(fmt.Sprintf("=== %s ===\n%s\n\n", f.Name(), string(content)))
+			// Fixed: use Fprintf instead of WriteString + Sprintf
+			fmt.Fprintf(&sb, "=== %s ===\n%s\n\n", f.Name(), string(content))
 		}
 	}
 

cmd/scaffold_test.go

@@ -58,7 +58,11 @@ func TestScaffoldCmd_Live(t *testing.T) {
 			tmpDir := t.TempDir()
 			origDir, _ := os.Getwd()
 			require.NoError(t, os.Chdir(tmpDir))
-			defer os.Chdir(origDir)
+			defer func() {
+				if err := os.Chdir(origDir); err != nil {
+					t.Logf("warning: failed to restore original directory: %v", err)
+				}
+			}()
 
 			rootCmd.SetArgs(tt.args)
 			err := rootCmd.Execute()