feat(udp): speak WSJT-X to Logger32, and lighten Sahara

"sent 1153 bytes to 127.0.0.1:2250" and nothing in Logger32. Both true: the
line the operator screenshotted is titled "Setup additional WSJT/JTDX UDP
sockets", and those receivers take UDP LOGGING PACKETS — the WSJT-X v2
protocol. A bare ADIF record posted to them is dropped without a word.

So there is a new outbound service rather than a change to the existing one:
"WSJT-X logged QSO (Logger32)" sends the same ADIF wrapped in a Logged ADIF
datagram (magic 0xadbccbda, schema 2, type 12), defaulting to port 2250. The
plain-text row stays for JTAlert/GridTracker-style receivers, because the two
really are different wire formats and one row cannot be both.

The id string is "OpsLog", not "WSJT-X": a receiver uses it to tell instances
apart, and impersonating the real thing would make a second WSJT-X
indistinguishable from us.

Tested both ways — the header byte for byte, and a round trip back through our
own ParseWSJT, since that is the same decoding every receiver applies.

Sahara moves to the parchment an operator asked for: page #e6ded0, panels
#f3eee2, toolbars #ded5c4, terracotta #c4501e on the buttons and the focus
ring. Lighter and less saturated than the deep sand it was.

internal/integrations/udp/config.go

@@ -37,6 +37,10 @@ const (
 	ServiceDBUpdated ServiceType = "db_updated"      // ADIF of each locally-logged QSO (on save)
 	ServicePstFreq   ServiceType = "pstrotator_freq" // <PST><FREQUENCY> radio freq (on freq change)
 	ServiceN1MMRadio ServiceType = "n1mm_radioinfo"  // N1MM RadioInfo XML: freq+mode (on freq/mode change)
+	// ServiceWSJTLog wraps the same ADIF in a WSJT-X "Logged ADIF" datagram.
+	// Logger32 and others listen on the WSJT-X interface, not for plain text, and
+	// discard a bare ADIF record without a word — so the two cannot be one row.
+	ServiceWSJTLog ServiceType = "wsjt_log"
 )
 
 // Config is one user-defined UDP connection.

internal/integrations/udp/outbound.go

@@ -103,6 +103,18 @@ func (m *Manager) EmitLoggedADIF(adif string) {
 	}
 }
 
+// EmitLoggedADIFWSJT sends the same record wrapped as a WSJT-X "Logged ADIF"
+// datagram, for receivers that speak that interface rather than plain text —
+// Logger32's additional UDP sockets among them.
+func (m *Manager) EmitLoggedADIFWSJT(adifRec string) {
+	if strings.TrimSpace(adifRec) == "" {
+		return
+	}
+	for _, c := range m.Outbound(ServiceWSJTLog) {
+		m.sendTo(c, BuildWSJTLoggedADIF("OpsLog", adifRec))
+	}
+}
+
 // sendTo resolves the row's destination (host:port) and fires one datagram.
 //
 // A successful send is logged, not just a failure. UDP has no delivery report:

internal/integrations/udp/wsjtsend.go

@@ -0,0 +1,50 @@
+package udp
+
+import (
+	"bytes"
+	"encoding/binary"
+)
+
+// Sending WSJT-X UDP messages, as opposed to parsing them (wsjt.go).
+//
+// This exists for Logger32, and for anything else that listens on the WSJT-X
+// interface rather than for plain text. Logger32's "additional WSJT/JTDX UDP
+// sockets" receivers — ports 2250, 2251, 2252 — are documented as receiving
+// "UDP logging packets": they speak the WSJT-X v2 protocol, and a raw ADIF
+// record posted to them is discarded without a word.
+//
+// That is a real distinction and not a detail: an operator can watch OpsLog
+// report "sent 1153 bytes to 127.0.0.1:2250" and see nothing whatsoever appear
+// in Logger32, because both statements are true.
+
+// buildQString encodes a Qt QString/QByteArray as QDataStream writes it: a
+// big-endian int32 length followed by the UTF-8 bytes. A negative length means
+// null, which is not what we ever want here — an empty string is length 0.
+func buildQString(s string) []byte {
+	out := make([]byte, 4, 4+len(s))
+	binary.BigEndian.PutUint32(out, uint32(len(s)))
+	return append(out, s...)
+}
+
+// BuildWSJTLoggedADIF frames a WSJT-X "Logged ADIF" datagram (message type 12).
+//
+//	uint32  magic   0xadbccbda
+//	uint32  schema  2
+//	uint32  type    12
+//	QString id      the sending program's name
+//	QString adif    the ADIF record
+//
+// id matters more than it looks: a receiver uses it to tell instances apart, and
+// some show it in their log. "OpsLog" is honest — pretending to be WSJT-X would
+// make a second instance of the real thing indistinguishable from us.
+func BuildWSJTLoggedADIF(id, adif string) []byte {
+	var b bytes.Buffer
+	var hdr [12]byte
+	binary.BigEndian.PutUint32(hdr[0:4], wsjtMagic)
+	binary.BigEndian.PutUint32(hdr[4:8], 2) // schema 2 — what WSJT-X 2.x speaks
+	binary.BigEndian.PutUint32(hdr[8:12], wsjtMsgLoggedADIF)
+	b.Write(hdr[:])
+	b.Write(buildQString(id))
+	b.Write(buildQString(adif))
+	return b.Bytes()
+}

internal/integrations/udp/wsjtsend_test.go

@@ -0,0 +1,49 @@
+package udp
+
+import (
+	"bytes"
+	"testing"
+)
+
+// What we send has to be what we can read back: Logger32 and the rest decode
+// this with the same rules our own parser uses, so a round trip through
+// ParseWSJT is the honest check.
+//
+// The case behind it: OpsLog reported "sent 1153 bytes to 127.0.0.1:2250" and
+// Logger32 showed nothing. Both were true — its UDP sockets speak the WSJT-X
+// protocol and discard a bare ADIF record without a word.
+func TestWSJTLoggedADIFRoundTrips(t *testing.T) {
+	const rec = "<CALL:5>VK9XX<BAND:3>20m<MODE:3>FT8<QSO_DATE:8>20260814<TIME_ON:6>174433<EOR>"
+	pkt := BuildWSJTLoggedADIF("OpsLog", rec)
+
+	ev, ok, err := ParseWSJT(pkt)
+	if err != nil {
+		t.Fatalf("ParseWSJT: %v", err)
+	}
+	if !ok {
+		t.Fatal("our own parser did not recognise the datagram we build")
+	}
+	if ev.LoggedADIF != rec {
+		t.Errorf("ADIF = %q, want %q", ev.LoggedADIF, rec)
+	}
+	if ev.ProgramID != "OpsLog" {
+		t.Errorf("id = %q, want OpsLog — a receiver uses it to tell instances apart", ev.ProgramID)
+	}
+}
+
+// The header is fixed and other programs match on it byte for byte.
+func TestWSJTLoggedADIFHeader(t *testing.T) {
+	pkt := BuildWSJTLoggedADIF("OpsLog", "<EOR>")
+	want := []byte{
+		0xad, 0xbc, 0xcb, 0xda, // magic
+		0x00, 0x00, 0x00, 0x02, // schema 2
+		0x00, 0x00, 0x00, 0x0c, // type 12 — Logged ADIF
+		0x00, 0x00, 0x00, 0x06, // len("OpsLog")
+		'O', 'p', 's', 'L', 'o', 'g',
+		0x00, 0x00, 0x00, 0x05, // len("<EOR>")
+		'<', 'E', 'O', 'R', '>',
+	}
+	if !bytes.Equal(pkt, want) {
+		t.Errorf("packet = % X\nwant     % X", pkt, want)
+	}
+}