feat: follow the SUB VFO over OmniRig; distance column in the QSO grids

OmniRig reports the VFO pair (AA/AB/BA/BB) on the whole Yaesu range and never
the single-letter form. Only the latter was honoured, so every rig in that
family stayed pinned to VFO A: pressing SUB moved the radio but not OpsLog,
and a QSO worked on SUB was logged on the main VFO's frequency. The first
letter of the pair is the VFO being listened on — Log4OM reads it and gets the
right frequency on the same rigs, which is what showed the data was there.
The enum now wins over the Yaesu Freq==FreqB inference, which is only a
fallback for a rig file that names no VFO at all (the stock FTDX10 one answers
neither VS; nor FR; usably — verified on the air).

Split: the ON flag is still latched to survive a rig file that flips it on its
own, but the latch is now ARMED only after 8 flips in 30 s. A first cut at
3-in-15s was armed by the operator toggling split while testing, imposing the
6 s clearing delay on a radio that did not need it; a misreading file flips a
dozen times in that window untouched, so the two cases separate cleanly.

Distance (km) column added to Recent QSOs and Worked before (shared catalog).
Computed from the QSO's OWN my_grid/my_lat/lon first, falling back to the
current profile's locator: a log spans years and portable outings, so the
station a QSO was made from is not necessarily today's.

Locator: a precise QRZ/HamQTH grid is no longer overwritten by the cty.dat
entity centroid. The lookup runs several times per QSO and the provider gets
2 s; a slow second answer fell back to cty.dat and downgraded JN05JG to JN16
while name and QTH survived (they are only written when non-empty).

The OmniRig diagnostic line now logs what OpsLog concluded, not just what
OmniRig reported. icomnet.go: gofmt alignment only.

changelog.json

@@ -1,4 +1,24 @@
 [
+  {
+    "version": "0.21.4",
+    "date": "2026-07-26",
+    "en": [
+      "OmniRig on an FTDX101D: the frequency follows the SUB VFO again, and split is detected. The stock rig file never names a single VFO — it reports only the A/B pair and alternates between the two values, split included, from one poll to the next. OpsLog now takes the displayed frequency as the reference on Yaesu and keeps a split reported once for a few seconds, so the contradicting reading no longer cancels it.",
+      "Recent QSOs and Worked before: new Distance (km) column, like the cluster's. It is computed from the QSO's own locator pair, so a contact made portable keeps the distance from where you actually were; QSOs with no locator on either side stay blank.",
+      "OmniRig: the frequency follows the SUB VFO on radios that report the two VFOs as a pair (AA / AB / BA / BB) — the whole Yaesu range. Only the single-VFO form was recognised, so pressing SUB left OpsLog on the main VFO, and a QSO worked on SUB was logged on the wrong frequency.",
+      "OmniRig split is held briefly ONLY for a radio whose rig file reports it erratically. On a radio that reports it correctly, split now clears the instant you cancel it on the front panel instead of a few seconds later.",
+      "The diagnostic log now records what OpsLog concluded from OmniRig (VFO, TX/RX frequencies, split), not just what OmniRig reported.",
+      "Locator: a precise grid from QRZ/HamQTH is no longer replaced by the country centroid (JN05JG becoming JN16 for a French station). The lookup runs more than once per QSO and the provider only gets two seconds to answer; on a slower connection the second answer fell back to cty.dat and downgraded the locator, while the name and QTH stayed — which made it look like QRZ had returned a wrong grid."
+    ],
+    "fr": [
+      "OmniRig sur FTDX101D : la fréquence suit de nouveau le VFO SUB, et le split est détecté. Le fichier radio d'origine ne nomme jamais un VFO seul — il ne rapporte que la paire A/B, et alterne entre les deux valeurs, split compris, d'une interrogation à l'autre. OpsLog prend désormais la fréquence affichée comme référence sur Yaesu et conserve quelques secondes un split annoncé une fois, pour que la lecture contradictoire ne l'annule plus.",
+      "QSO récents et Déjà contacté : nouvelle colonne Distance (km), comme celle du cluster. Elle est calculée à partir des locators propres au QSO, si bien qu'un contact fait en portable garde la distance depuis l'endroit où vous étiez réellement ; les QSO sans locator d'un côté ou de l'autre restent vides.",
+      "OmniRig : la fréquence suit le VFO SUB sur les radios qui rapportent les deux VFO sous forme de paire (AA / AB / BA / BB) — toute la gamme Yaesu. Seule la forme à un seul VFO était reconnue, si bien qu'un passage sur SUB laissait OpsLog sur le VFO principal, et qu'un QSO fait sur SUB était enregistré sur la mauvaise fréquence.",
+      "Le split OmniRig n'est maintenu brièvement que pour une radio dont le fichier de définition le rapporte de façon erratique. Sur une radio qui le rapporte correctement, le split disparaît désormais dès que vous le coupez en façade, au lieu de quelques secondes plus tard.",
+      "Le journal de diagnostic enregistre maintenant ce qu'OpsLog a déduit d'OmniRig (VFO, fréquences TX/RX, split), et pas seulement ce qu'OmniRig a rapporté.",
+      "Locator : un locator précis venu de QRZ/HamQTH n'est plus remplacé par le centre du pays (JN05JG devenant JN16 pour une station française). La recherche est lancée plusieurs fois par QSO et le fournisseur ne dispose que de deux secondes ; sur une connexion plus lente, la seconde réponse retombait sur cty.dat et dégradait le locator, alors que le nom et le QTH restaient — d'où l'impression que QRZ renvoyait un mauvais locator."
+    ]
+  },
   {
     "version": "0.21.3",
     "date": "2026-07-25",