feat: Flex stays on the RX slice in split

SmartSDR moves its active flag onto the TX slice as soon as the transmit
frequency is touched, and OpsLog followed it. But the operator is listening to
the DX on the other slice: the S-meter, audio level, filter and DSP they are
adjusting all belong there, so following the transmitter handed them the
controls of a receiver they were not using.

In split the receive slice now wins. Simplex is unchanged, and two same-band
slices in different classes (SSB alongside FT8) are still not a split.

A slice clicked IN OPSLOG is remembered and overrides both the split rule and
the radio's focus — that is the operator speaking. Activating a slice on the
radio or in SmartSDR deliberately does not move OpsLog. The pin is dropped when
that slice stops being in use, so a closed receiver cannot strand the display.

The panel now highlights the slice OpsLog is working with rather than the radio's
focused one; reporting the radio's flag would light up one slice while every
control acted on another.

changelog.json

@@ -1,4 +1,14 @@
 [
+  {
+    "version": "0.22.4",
+    "date": "",
+    "en": [
+      "FlexRadio: in split, OpsLog stays on the receive slice instead of following the transmitter, so the S-meter, audio and DSP are those of the station being worked. Clicking a slice in OpsLog still selects it; selecting one on the radio does not move OpsLog."
+    ],
+    "fr": [
+      "FlexRadio : en split, OpsLog reste sur la slice de réception au lieu de suivre l'émission — S-mètre, audio et DSP sont ceux de la station travaillée. Cliquer une slice dans OpsLog la sélectionne toujours ; en choisir une sur la radio ne déplace pas OpsLog."
+    ]
+  },
   {
     "version": "0.22.3",
     "date": "",