fix(icom): a set whose acknowledgement is lost is sent once more

Extends to frequency and mode what PTT already had. A missing FB is not a
missing command: the rig acts on the frame as it decodes it, and what
expires is our wait for the answer, on a bus shared with the rig's own
transceive updates. JTDX in "Split: Fake It" moves the dial and the mode
immediately before every key-down, so those acks queue behind each other.

Losing one is fatal to the client rather than merely untidy: rigctld answers
RPRT -9, JTDX reads that as losing rig control and tears the connection down
mid-over. An operator's log shows three set_freq failures and one set_mode,
each followed within 300 ms by a fresh rigctld client -- and shows the PTT
resend rescuing an over that would otherwise have ended there.

Opt-in per caller rather than folded into exec: only a command that says
"be in this state" can be repeated safely, and a relative one must never
come through here.

The acknowledgement loss itself is still unexplained. Every failure in that
log is preceded by a state read reporting SSB on a rig in DATA, which points
at CI-V frame desync rather than a slow rig, and needs a trace to pin down.

changelog.json

@@ -1,4 +1,18 @@
 [
+  {
+    "version": "0.25.9",
+    "date": "",
+    "en": [
+      "The band/mode matrix colours can be chosen in Appearance, starting from the ones your theme already paints. Its legend is translated too.",
+      "TCI sharing: a refused un-key no longer leaves the rig stuck transmitting, and PTT is dropped if the client dies mid-over.",
+      "Icom: a frequency or mode change whose acknowledgement is lost is sent again, like PTT — losing one made JTDX drop the radio."
+    ],
+    "fr": [
+      "Les couleurs de la matrice bandes/modes se choisissent dans Apparence, à partir de celles du thème. Sa légende est traduite aussi.",
+      "Partage TCI : un retour en réception refusé ne laisse plus le poste bloqué en émission, et le PTT retombe si le logiciel meurt.",
+      "Icom : un changement de fréquence ou de mode dont l’accusé se perd est renvoyé, comme le PTT — en perdre un faisait lâcher JTDX."
+    ]
+  },
   {
     "version": "0.25.8",
     "date": "",