fix: remove --tray flag for Linux server launch

The Linux server binary is built with CGO_ENABLED=0 and -tags notray,
so --tray is not available. The systemd service and LaunchServer now
start the server without the --tray flag on Linux.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

edge-ai-platform/installer/app.go

@@ -648,11 +648,13 @@ func (inst *Installer) LaunchServer() (string, error) {
 
 	// Read config to get relay args
 	// Windows: use --gui (web-based controller, no CGO needed)
-	// macOS/Linux: use --tray (system tray, CGO-enabled build)
+	// macOS: use --tray (system tray, CGO-enabled build)
+	// Linux: no flag (headless server, no tray/gui)
 	var args []string
-	if runtime.GOOS == "windows" {
+	switch runtime.GOOS {
+	case "windows":
 		args = append(args, "--gui")
-	} else {
+	case "darwin":
 		args = append(args, "--tray")
 	}
 	cfgPath := filepath.Join(platformConfigDir(), "config.json")

edge-ai-platform/installer/platform_linux.go

@@ -85,7 +85,7 @@ func installAutoRestart(installDir string) error {
 		"",
 		"[Service]",
 		"Type=simple",
-		"ExecStart=" + binPath + " --tray",
+		"ExecStart=" + binPath,
 		"WorkingDirectory=" + installDir,
 		"Restart=on-failure",
 		"RestartSec=5",