fix: check f.Close error in TestLoadConfigFile

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Mickaël Canévet <mickael.canevet@proton.ch>

Author: mcanevet

main_test.go

@@ -284,7 +284,9 @@ func TestLoadConfigFile(t *testing.T) {
 	if _, err := f.Write(content); err != nil {
 		t.Fatal(err)
 	}
-	f.Close()
+	if err := f.Close(); err != nil {
+		t.Fatal(err)
+	}
 
 	got, err := loadConfig(f.Name(), "", false)
 	if err != nil {