fix: a cluster spot dragged the rig from SUB back to MAIN

Reported on an FTDX101 (F4NBZ): listening on the SUB VFO, clicking a spot moved
the radio to MAIN.

SetSimplexMode is the first thing SetFrequency tries, and it means "receive and
transmit here, simplex" — OmniRig applies that to the MAIN VFO by definition. It
is there because several Icoms ignore direct FreqA/FreqB writes, so it stays for
the main VFO; on SUB it is now skipped entirely and FreqB carries the change.

The generic "Freq" property is skipped on SUB too: on several rig files it IS the
main VFO, so writing it would move the VFO the operator is not using — or pull
them back to it, which is the bug being fixed.

An operator on SUB put themselves there deliberately. A spot click asks for a
frequency, not for a change of VFO — that distinction is the whole fix, and a
test pins which property each VFO state writes.

changelog.json

@@ -1,4 +1,14 @@
 [
+  {
+    "version": "0.22.1",
+    "date": "2026-07-29",
+    "en": [
+      "Clicking a cluster spot while listening on the SUB VFO no longer pulls the radio back to MAIN. The command used to tune sets the main VFO by definition; on SUB the sub VFO is now written directly and the VFO selection is left alone."
+    ],
+    "fr": [
+      "Cliquer sur un spot du cluster en écoutant sur le VFO SUB ne ramène plus la radio sur le VFO principal. La commande utilisée pour s'accorder agit par définition sur le VFO principal ; sur SUB, c'est désormais le VFO secondaire qui est écrit, sans toucher à la sélection."
+    ]
+  },
   {
     "version": "0.22.0",
     "date": "2026-07-28",