feat(sat): PstRotator can point the antenna too

It handles azimuth and elevation, and a great many stations already run
it in front of a controller OpsLog has never heard of. For those,
OpsLog talking to the controller itself would be a second program
fighting PstRotator over the same cable — so it hands over the bearing
instead, and lets PstRotator turn the mast.

Both kinds sit behind one small interface, chosen in Settings. Neither is
more correct than the other: the right one is whichever the station
already has working.

The 450° overlap is deliberately NOT applied on the PstRotator path.
PstRotator knows which machine is on the other end and does its own; two
programs each deciding to go the long way round is exactly how an antenna
unwinds in the middle of a pass.

Position queries are asked at most every three seconds rather than on
every tick. A PstRotator query binds a socket and waits up to a second
and a half, and many setups answer nothing at all — so one silence is
enough and it stops asking, reporting the commanded position instead and
saying that is what it is.

app_sat.go

@@ -37,7 +37,14 @@ const (
 	// The az/el rotator. Its own settings rather than the HF rotator's: a
 	// satellite station's elevation rotator is a different machine on a
 	// different port, and an operator who has both must not have to choose.
-	keySatRotOn        = "sat.rot_enabled"
+	keySatRotOn = "sat.rot_enabled"
+	// Which program drives the mast: OpsLog itself over EasyComm, or PstRotator,
+	// which many stations already run in front of their controller. Its own port
+	// key because it is a different program on a different port from an EasyComm
+	// controller, and an operator who tries both must not lose the first setting
+	// to the second.
+	keySatRotType      = "sat.rot_type"      // "easycomm" | "pstrotator"
+	keySatRotPstPort   = "sat.rot_pst_port"  // PstRotator's UDP command port
 	keySatRotTransport = "sat.rot_transport" // "serial" | "tcp"
 	keySatRotHost      = "sat.rot_host"
 	keySatRotPort      = "sat.rot_port"
@@ -68,6 +75,8 @@ type SatSettings struct {
 
 	// The az/el rotator.
 	RotOn        bool   `json:"rot_on"`
+	RotType      string `json:"rot_type"`
+	RotPstPort   int    `json:"rot_pst_port"`
 	RotTransport string `json:"rot_transport"`
 	RotHost      string `json:"rot_host"`
 	RotPort      int    `json:"rot_port"`
@@ -236,6 +245,7 @@ func (a *App) satSettings() SatSettings {
 	// from being a command a second.
 	out := SatSettings{
 		MinEl: 10, WindowH: 24, AutoTLE: true,
+		RotType: satRotEasycomm, RotPstPort: 12000,
 		RotTransport: "serial", RotPort: 4533, RotBaud: 9600,
 		RotMaxAz: 360, RotMinEl: 0, RotStep: 5,
 	}
@@ -244,12 +254,18 @@ func (a *App) satSettings() SatSettings {
 	}
 	m, err := a.settings.GetMany(a.ctx,
 		keySatFavorites, keySatMinEl, keySatWindowH, keySatAutoTLE, keySatGrid, keySatAltM,
-		keySatRotOn, keySatRotTransport, keySatRotHost, keySatRotPort, keySatRotCOM,
+		keySatRotOn, keySatRotType, keySatRotPstPort, keySatRotTransport, keySatRotHost, keySatRotPort, keySatRotCOM,
 		keySatRotBaud, keySatRotMaxAz, keySatRotMinEl, keySatRotStep, keySatRotPark)
 	if err != nil {
 		return out
 	}
 	out.RotOn = m[keySatRotOn] == "1"
+	if ty := m[keySatRotType]; ty == satRotPst || ty == satRotEasycomm {
+		out.RotType = ty
+	}
+	if v, err := strconv.Atoi(m[keySatRotPstPort]); err == nil && v > 0 && v <= 65535 {
+		out.RotPstPort = v
+	}
 	if tr := m[keySatRotTransport]; tr == "tcp" || tr == "serial" {
 		out.RotTransport = tr
 	}
@@ -321,6 +337,12 @@ func (a *App) SaveSatSettings(s SatSettings) error {
 		seen[strings.ToUpper(n)] = true
 		favs = append(favs, n)
 	}
+	if s.RotType != satRotPst {
+		s.RotType = satRotEasycomm
+	}
+	if s.RotPstPort <= 0 || s.RotPstPort > 65535 {
+		s.RotPstPort = 12000
+	}
 	if s.RotTransport != "tcp" {
 		s.RotTransport = "serial"
 	}
@@ -344,6 +366,8 @@ func (a *App) SaveSatSettings(s SatSettings) error {
 		keySatGrid:         strings.ToUpper(strings.TrimSpace(s.Grid)),
 		keySatAltM:         strconv.Itoa(s.AltM),
 		keySatRotOn:        boolStr(s.RotOn),
+		keySatRotType:      s.RotType,
+		keySatRotPstPort:   strconv.Itoa(s.RotPstPort),
 		keySatRotTransport: s.RotTransport,
 		keySatRotHost:      strings.TrimSpace(s.RotHost),
 		keySatRotPort:      strconv.Itoa(s.RotPort),