feat(agent): send stream port and IPs in register request

Include StreamPort, LanIP, and TailscaleIP in RegisterRequest so the
server knows the agent's stream endpoints from the moment it registers,
not just after the first heartbeat. Align HeartbeatRequest field order
with RegisterRequest for consistency.

internal/agent/daemon.go

@@ -94,6 +94,9 @@ func (d *Daemon) Register(ctx context.Context) error {
 		Arch:        runtime.GOARCH,
 		Version:     d.cfg.Version,
 		DownloadDir: d.cfg.DownloadDir,
+		StreamPort:  d.cfg.StreamPort,
+		LanIP:       d.cfg.LanIP,
+		TailscaleIP: d.cfg.TailscaleIP,
 	}
 	if free, total, err := DiskInfo(d.cfg.DownloadDir); err == nil {
 		req.DiskFreeBytes = free