feat(tci): name the transmit audio source when keying, per the protocol

The specification settles what a night of experiments could only guess at.
TRX takes an optional THIRD argument naming the signal source — tci, mic1,
mic2, micPC, ecoder2 — and TCI 2.0 says it plainly: 'The signal for
transmitting is always taken from the microphone selected in the
ExpertSDR3. If a third-party software connected via TCI wants to transmit
its audio signal, you must specify the third argument - TCI.'

Without it the radio sends no chrono at all, whatever the mode. That is
what the SSB attempts ran into, and what was misread here as 'digital
modes only' — the mode was never the rule, the missing argument was.

So OpsLog says it, following the 'To radio' device: 'tci' when the voice
keyer owns the transmission, nothing at all otherwise, which leaves the
operator's own microphone alone for every other PTT. Nobody has to find
that setting in ExpertSDR3 and set it again for every mode, which is how
it is remembered there.

Two more things from the same document. A chrono with no audio ready is
now answered with silence rather than left unanswered — the vendor calls
that preferable. And the receive stream declares float32 and two channels
instead of trusting the defaults: they are the documented defaults, but a
default is something another program sharing this radio can have changed,
and a stream in an unexpected format is heard as noise rather than as a
mistake.

changelog.json

@@ -4,13 +4,13 @@
     "date": "",
     "en": [
       "SunSDR / ExpertSDR3: the radio's audio now travels over the TCI link itself. Pick 'Radio (TCI network audio)' as the From Radio or To Radio device and the QSO recorder and the voice keyer work with no virtual cable, no second sound card and nothing to set up in the Windows mixer.",
-      "For transmit, ExpertSDR3's own transmit audio source must be set to TCI rather than the microphone — it is remembered per mode, so setting it in SSB does not set it in DIGU. OpsLog says so within a fifth of a second rather than transmitting silence.",
+      "Transmitting over TCI needs no setting up in ExpertSDR3. The audio source is named each time OpsLog keys the radio, so it works in SSB as well as in the digital modes, and the microphone stays the source for every transmission that is not a voice message.",
       "Awards, RDA district comparison: the list stays where it was put. It was thrown back to the first row every three seconds, which made a long list of contacts to correct impossible to work through.",
       "Elecraft console: the SWR bar works. The radio answers SW; with three digits in tenths of a ratio — SW023 is 2.3:1 — and OpsLog was reading four, so every answer was discarded and the bar stayed empty."
     ],
     "fr": [
       "SunSDR / ExpertSDR3 : l'audio de la radio passe désormais par la liaison TCI elle-même. Choisis « Radio (TCI network audio) » comme périphérique From Radio ou To Radio et l'enregistreur de QSO comme le manipulateur vocal fonctionnent sans câble virtuel, sans seconde carte son et sans rien à régler dans le mixeur Windows.",
-      "Pour l'émission, la source audio d'émission d'ExpertSDR3 doit être réglée sur TCI et non sur le micro — elle est mémorisée par mode, donc la régler en SSB ne la règle pas en DIGU. OpsLog le dit en deux dixièmes de seconde au lieu d'émettre du silence.",
+      "Émettre par TCI ne demande aucun réglage dans ExpertSDR3. La source audio est nommée à chaque fois qu'OpsLog passe en émission, donc cela fonctionne en SSB comme en numérique, et le micro reste la source pour toute émission qui n'est pas un message vocal.",
       "Diplômes, comparaison des districts RDA : la liste reste où on l'a laissée. Elle revenait à la première ligne toutes les trois secondes, ce qui rendait impraticable une longue liste de contacts à corriger.",
       "Console Elecraft : la barre de ROS fonctionne. La radio répond à SW; par trois chiffres en dixièmes de rapport — SW023 vaut 2,3:1 — et OpsLog en lisait quatre, si bien que chaque réponse était jetée et la barre restait vide."
     ]