Append an optional station log and announce the software after login.

A log path that cannot be written leaves the station on the reflector, and the reflector learns which program joined.

Co-authored-by: Cursor <cursoragent@cursor.com>

station/reflector_test.go

@@ -2,6 +2,7 @@ package station_test
 
 import (
 	"encoding/binary"
+	"encoding/json"
 	"io"
 	"net"
 	"os"
@@ -283,6 +284,21 @@ func takeU32(t *testing.T, b []byte) (uint32, []byte) {
 	return binary.BigEndian.Uint32(b[:4]), b[4:]
 }
 
+func requireSoftwareIdentity(t *testing.T, body []byte) {
+	t.Helper()
+	raw, rest := takeStr(t, body)
+	if len(rest) != 0 {
+		t.Fatalf("software identity has %d trailing bytes", len(rest))
+	}
+	var got map[string]string
+	if err := json.Unmarshal([]byte(raw), &got); err != nil {
+		t.Fatalf("software identity %q: %v", raw, err)
+	}
+	if len(got) != 2 || got["sw"] != station.SoftwareName || got["swVer"] != station.SoftwareVersion {
+		t.Fatalf("software identity = %#v, want sw %q and swVer %q only", got, station.SoftwareName, station.SoftwareVersion)
+	}
+}
+
 func takeStr(t *testing.T, b []byte) (string, []byte) {
 	t.Helper()
 	n, rest := takeU16(t, b)