fix(boot-test): fill {PUBLIC_*} in the startup command like the panel does

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MZxvxViV6QwAtVWT3saGvs

cmd/gbrgames/boottest.go

@@ -153,6 +153,13 @@ func bootTestPayload(gamesDir, id string, fillBlank bool) (map[string]any, error
 		}
 	}
 
+	// The panel fills {PUBLIC_IP}, {PUBLIC_HOST} and {PUBLIC_PORT_n} in the startup command too
+	startup := g["defaultStartupCommand"]
+	if cmd, ok := startup.(string); ok {
+		cmd = strings.NewReplacer("{PUBLIC_IP}", "127.0.0.1", "{PUBLIC_HOST}", "127.0.0.1").Replace(cmd)
+		startup = publicPort.ReplaceAllString(cmd, "$1")
+	}
+
 	return map[string]any{
 		"command":       "DEPLOY_SERVER",
 		"serverId":      "boottest-" + id,
@@ -166,7 +173,7 @@ func bootTestPayload(gamesDir, id string, fillBlank bool) (map[string]any, error
 		"configFilePath":      g["configFilePath"],
 		"configFileFormat":    g["configFileFormat"],
 		"configFormatOptions": g["configFormatOptions"],
-		"startupCommand":      g["defaultStartupCommand"],
+		"startupCommand":      startup,
 		"memoryLimitMb":       g["requiredMemoryMb"],
 		"containerUser":       g["containerUser"],
 		"dockerNetwork":       bootTestNetwork,