Install writes a fully commented sample env file when no config exists

internal/service/service_windows.go

@@ -172,10 +172,16 @@ func Install(configPath string, copyBin bool) error {
 				}
 			}
 		}
-		// A service has no console: without LOG_FILE the output vanishes, so
-		// the installed env file defaults to logging into ProgramData. An
-		// existing LOG_FILE setting is left alone.
-		if err := ensureLogFile(targetCfg, filepath.Join(dataDir, "gpu-turnstile.log")); err != nil {
+		// A service has no console: without LOG_FILE the output vanishes.
+		// With no config at all, install a fully commented sample covering
+		// every setting (only LOG_FILE active); an existing config just gets
+		// a LOG_FILE line appended if it has none.
+		logPath := filepath.Join(dataDir, "gpu-turnstile.log")
+		if _, statErr := os.Stat(targetCfg); os.IsNotExist(statErr) {
+			if err := os.WriteFile(targetCfg, []byte(config.SampleEnv(logPath)), 0o644); err != nil {
+				return fmt.Errorf("write %s: %w", targetCfg, err)
+			}
+		} else if err := ensureLogFile(targetCfg, logPath); err != nil {
 			return err
 		}
 		configPath = targetCfg