feat(rotator): one list of rotator interfaces, and ERC-M

The satellite page configured its own EasyComm or PstRotator link while five
other backends were configured in the rotator list. An operator with one az/el
mast therefore described it twice, and could describe it differently the second
time — a station that works on HF and not on a pass, for no reason visible
anywhere on screen.

Now every interface lives in Settings ▸ Rotator, once, and the satellite page
stores only a KEY into that list plus the tracking policy that is genuinely its
own (minimum elevation, step, park). The key and not the index: deleting the
first rotor must not silently point the tracker at a different mast.
migrateSatRotator() turns an existing satellite link into a real entry in the
list, selects it, and clears the old keys so it cannot run twice.

Which rotors have an elevation axis is now a question with one answer, in Go:
rotatorTypes plus rotorHasElevation, exposed to the panel by GetRotatorTypes.
The dropdown, the labels, each backend's default port and default baud all come
from there, so TypeScript no longer keeps a second copy of the same knowledge to
drift out of step. Three cases do not follow from the type alone and are treated
as such: PstRotator forwards elevation to a mast that may not have any, so the
operator says; a SPID's dialect decides (Rot1Prog has no elevation in its reply
format); and an ARCO and an ERC-M speak the same GS-232 while only one of them
lifts.

Each interface carries an Az / Az+El badge beside it. The satellite rotor
dropdown LISTS the azimuth-only ones, disabled, rather than hiding them: an
operator who owns one rotator and does not see it concludes OpsLog cannot find
it, where a greyed row saying "azimuth only" teaches the actual thing.

ERC-M by DF9GR is new — the az/el interface for a Yaesu G-5500. It emulates
GS-232, so internal/rotator/gs232 grew the elevation half: W for a two-axis
move, C2 to read both, falling back to C+B for the firmware that answers C2 with
the azimuth alone. That fallback is the point of the parser tests: reading such
a reply as "elevation zero" would put the antenna on the horizon, which is the
one wrong answer that looks plausible.

EasyComm II is promoted to an ordinary rotator interface, so it can also turn
the antenna from the compass and from a spot click.

The ERC-M is UNTESTED on hardware. Its Test button reads BOTH axes rather than
just the azimuth, so a controller wired for azimuth alone says so there instead
of during a pass.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

changelog.json

@@ -1,4 +1,20 @@
 [
+  {
+    "version": "0.27.20",
+    "date": "",
+    "en": [
+      "Every rotator interface now lives in Settings ▸ Rotator, and the satellite page only picks one of them. EasyComm and PstRotator used to be described inside the satellite settings while the other backends were described in the rotator list, so one mast was configured twice. What you already set up is moved into the list for you and selected.",
+      "Each rotator interface says whether it drives azimuth alone or azimuth and elevation, beside the interface itself. The satellite rotator list shows the azimuth-only ones greyed out rather than hiding them, so a rotor that cannot follow a pass says why.",
+      "New rotator interface: ERC-M by DF9GR, the azimuth/elevation controller for a Yaesu G-5500. Over its USB COM port or the network, with its emulation set to GS-232. Untested on hardware — reports welcome.",
+      "EasyComm II is now an ordinary rotator interface, so it can turn the antenna from the compass and from a spot click, not only during a satellite pass."
+    ],
+    "fr": [
+      "Toutes les interfaces de rotor sont désormais dans Réglages ▸ Rotator, et la page satellite ne fait qu’en choisir une. EasyComm et PstRotator se configuraient dans les réglages satellite pendant que les autres se configuraient dans la liste des rotors : un même pylône était décrit deux fois. Ce que vous aviez réglé est déplacé dans la liste et sélectionné automatiquement.",
+      "Chaque interface de rotor indique si elle pilote l’azimut seul ou l’azimut et l’élévation, juste à côté de l’interface. La liste des rotors de la page satellite affiche les azimut-seul en grisé plutôt que de les cacher : un rotor qui ne peut pas suivre un passage dit pourquoi.",
+      "Nouvelle interface de rotor : ERC-M de DF9GR, le contrôleur azimut/élévation pour un Yaesu G-5500. Via son port COM USB ou le réseau, avec son émulation réglée sur GS-232. Non testé sur matériel — vos retours sont les bienvenus.",
+      "EasyComm II devient une interface de rotor comme les autres : elle peut tourner l’antenne depuis le compas et depuis un clic sur un spot, plus seulement pendant un passage satellite."
+    ]
+  },
   {
     "version": "0.27.19",
     "date": "",