fix(winkeyer): send the probe the way a working client sends it

Logger32's WinKeyer debug against the K3NG that will not answer OpsLog is a
capture of the exchange working, on the same keyer and the same port:

    Sent: 13 13 13 00 04 55
    Rcvd: 55            (72 ms)
    Sent: 00 02  Host open
    Rcvd: 23            (WK2 v23)

That is the sequence I already send. The difference is the grouping: Logger32
puts the three nulls and the echo probe in ONE write, and we split them with a
50 ms pause and a buffer purge in between. On a keyer that reboots when the
port opens, that pause is a window for it to come up mid-sequence and swallow
half of it — and there was nothing to wait for, since a null produces no reply.

The handshake bytes are now logged unconditionally, not behind the diagnostic
option. "No WinKeyer answered" cannot be told apart from a wrong port, a wrong
baud rate, a keyer still booting, or another program holding the line. The
bytes can, and it is four lines per connect attempt.

changelog.json

@@ -2,8 +2,12 @@
   {
     "version": "0.25.4",
     "date": "",
-    "en": [],
-    "fr": []
+    "en": [
+      "WinKeyer: the opening probe goes out as one write, matching a capture of a client that talks to the same K3NG keyer, and the handshake bytes are always logged so a keyer that stays silent can be diagnosed."
+    ],
+    "fr": [
+      "WinKeyer : la sonde d’ouverture part en un seul envoi, calquée sur la capture d’un client qui dialogue avec le même manipulateur K3NG, et les octets de la poignée de main sont toujours journalisés pour diagnostiquer un manipulateur muet."
+    ]
   },
   {
     "version": "0.25.3",