feat: IC-7300MKII, and two Icom addresses that were plain wrong

Adds the IC-7300MKII at CI-V 0xB6.

Doing so exposed a drift between the two hand-kept copies of the model table: the
settings offered the IC-7700 at 0x88 and the IC-7800 at 0x80, which are the
IC-7100's and the IC-7410's factory addresses. Picking either set an address the
rig never answers on — the symptom is a radio that simply stays silent — and the
backend then named it as the other model. Corrected to 0x74 and 0x6A, and the
four models the backend already knew (IC-7100, IC-7410, IC-7600, IC-7851) are now
offered too instead of forcing a manual address.

A test reads the model list out of the .tsx and asserts civ.ModelName agrees, so
the next model added on one side alone fails the build rather than someone's
radio.

frontend/src/components/SettingsModal.tsx

@@ -1006,12 +1006,20 @@ function FlexBandAntennasPanel({ bands }: { bands: string[] }) {
 // model sets icom_addr so the backend identifies it (civ.ModelName) and the UI
 // adapts (e.g. the attenuator steps differ by model). Keep in lockstep with
 // civ.ModelName in internal/cat/civ/civ.go. `addr` is decimal.
+// The IC-7700 and IC-7800 were listed at 0x88 and 0x80 — which are the IC-7100's
+// and the IC-7410's. Picking one of them set an address the rig never answers on,
+// and the backend then named it as the other model.
 const ICOM_MODELS: { name: string; addr: number }[] = [
   { name: 'IC-705', addr: 0xA4 },
+  { name: 'IC-7100', addr: 0x88 },
   { name: 'IC-7300', addr: 0x94 },
+  { name: 'IC-7300MKII', addr: 0xB6 },
+  { name: 'IC-7410', addr: 0x80 },
+  { name: 'IC-7600', addr: 0x7A },
   { name: 'IC-7610', addr: 0x98 },
-  { name: 'IC-7700', addr: 0x88 },
-  { name: 'IC-7800', addr: 0x80 },
+  { name: 'IC-7700', addr: 0x74 },
+  { name: 'IC-7800', addr: 0x6A },
+  { name: 'IC-7851', addr: 0x8E },
   { name: 'IC-9100', addr: 0x7C },
   { name: 'IC-9700', addr: 0xA2 },
 ];