feat(cat): share the rig over TCI as well as Hamlib — one or the other

internal/rigctld exists because Windows gives a COM port to ONE process: the
moment OpsLog talks to the radio natively, nothing else can. It answers the
programs that speak Hamlib NET rigctl. This answers the ones built around Expert
Electronics' TCI instead — and it answers them whatever radio is connected,
because it sits on the same backend-agnostic Rig interface. An operator with an
Icom or a Yaesu can now hand a TCI-only program a working rig.

One server or the other, never both. They answer the same questions about the
same radio, nothing speaks both, and a second listener is only a second thing to
go wrong.

Written against the official TCI Protocol document (ExpertSDR3/TCI, 12 January
2024, MIT — downloaded and read, not recalled): the initialisation set of §4.1
in its documented order, and the argument order of every command from §4.2. A
client will not proceed past connect without that block, which is why it is
written out in full rather than stubbed.

The one dangerous detail is the VFO mapping. TCI's channel A is where you
LISTEN and channel B where you transmit — the opposite way round from OpsLog's
RigState, which follows ADIF. Getting that backwards would put a station on the
DX's own frequency, so it is pinned in both directions by a test, and RxFreq was
added to the adapter rather than inferred.

Writing channel B while the rig is simplex is ignored: the client asked to
prepare a split transmit frequency, not to QSY, and a logger doing that on every
spot click would drag the operator off the station they were listening to. A
backend that cannot split still refuses out loud.

Only changes are pushed. TCI clients redraw on each command, so re-sending an
unchanged frequency four times a second makes a VFO readout flicker and fights
the operator's own tuning.

Nine tests, no socket needed — the protocol is the decision, not the transport.

changelog.json

@@ -3,10 +3,12 @@
     "version": "0.25.8",
     "date": "",
     "en": [
-      "An entity that is a single island group now fills the IOTA reference on its own — no callbook subscription needed."
+      "An entity that is a single island group now fills the IOTA reference on its own — no callbook subscription needed.",
+      "CAT sharing can now speak TCI instead of Hamlib, so a TCI-only program reaches whatever radio OpsLog is on."
     ],
     "fr": [
-      "Une entité qui est un seul groupe d’îles remplit désormais la référence IOTA toute seule, sans abonnement callbook."
+      "Une entité qui est un seul groupe d’îles remplit désormais la référence IOTA toute seule, sans abonnement callbook.",
+      "Le partage CAT peut désormais parler TCI au lieu de Hamlib : un logiciel TCI atteint la radio, quelle qu’elle soit."
     ]
   },
   {