fix: ground-truth CI-V offset/tone on live ID-5100

- offset amount (0x0D) is REJECTED (NG) by the radio -> removed the offset
  codec + set_offset/get_offset; tune_repeater now sets only duplex direction
  (radio applies its configured auto-offset)
- repeater tone (0x1B/00) uses a 3-byte field (00 + 2-byte BCD); set_tone
  prepends the pad, get_tone strips it
- duplex (0x0F) and tone-switch (0x16/42) verified working
- added get_duplex; verified full tune_repeater on a live repeater (all steps OK)

radio.py

@@ -157,35 +157,39 @@ class Radio:
         data = self.transact(civ.CMD_METER, bytes([civ.SUB_SQL_STATUS])).data
         return bool(data[1]) if len(data) > 1 else False
 
-    # ---- repeater config (candidate commands; verify live) ----------------
+    # ---- repeater config (verified on live ID-5100 2026-06-14) ------------
+    # Offset *amount* is not CI-V-settable on this radio (cmd 0x0D -> NG); the
+    # radio applies its configured auto-offset when a duplex direction is set.
     def set_duplex(self, direction):
-        """direction: '+', '-', or 'simplex'."""
+        """direction: '+', '-', or 'simplex'. Radio uses its configured offset."""
         code = {"+": civ.DUP_PLUS, "-": civ.DUP_MINUS,
                 "simplex": civ.DUP_SIMPLEX}.get(direction)
         if code is None:
             raise ValueError(f"bad duplex {direction!r}")
         return self._command(civ.CMD_DUPLEX, bytes([code]))
 
-    def set_offset(self, hz):
-        return self._command(civ.CMD_OFFSET, civ.offset_to_bcd(hz))
-
-    def get_offset(self):
-        return civ.bcd_to_offset(self.transact(civ.CMD_OFFSET).data)
+    def get_duplex(self):
+        code = self.transact(civ.CMD_DUPLEX).data[0]
+        return {civ.DUP_PLUS: "+", civ.DUP_MINUS: "-",
+                civ.DUP_SIMPLEX: "simplex"}.get(code, f"0x{code:02X}")
 
     def set_tone(self, hz):
+        # wire format: sub(0x00) + 0x00 pad + 2-byte BCD (00 00 08 85 = 88.5 Hz)
         return self._command(civ.CMD_TONE_PARAM,
-                             bytes([civ.SUB_RPT_TONE]) + civ.tone_to_bcd(hz))
+                             bytes([civ.SUB_RPT_TONE, 0x00]) + civ.tone_to_bcd(hz))
 
     def get_tone(self):
+        # reply data = sub + pad + 2-byte BCD; take the last two bytes
         return civ.bcd_to_tone(self.transact(civ.CMD_TONE_PARAM,
-                                             bytes([civ.SUB_RPT_TONE])).data[1:])
+                                             bytes([civ.SUB_RPT_TONE])).data[2:])
 
     def set_tone_on(self, on):
         return self._command(civ.CMD_TONE_SWITCH,
                              bytes([civ.SUB_TONE_ENC, 0x01 if on else 0x00]))
 
     def tune_repeater(self, rec):
-        """Apply a normalized record: freq -> duplex/offset -> tone.
+        """Apply a normalized record: freq -> duplex direction -> tone.
+        Offset amount comes from the radio's own config (not CI-V-settable).
         Returns (steps, errors): each step True/False; errors keyed by step."""
         steps, errors = {}, {}
 
@@ -196,10 +200,7 @@ class Radio:
                 steps[name] = False; errors[name] = str(e)
 
         attempt("freq", lambda: self.set_frequency(int(round(rec["output_mhz"] * 1e6))))
-        duplex = rec.get("duplex", "simplex")
-        attempt("duplex", lambda: self.set_duplex(duplex))
-        if duplex != "simplex":
-            attempt("offset", lambda: self.set_offset(int(round(rec.get("offset_mhz", 0) * 1e6))))
+        attempt("duplex", lambda: self.set_duplex(rec.get("duplex", "simplex")))
         if rec.get("tone_mode") == "ctcss" and rec.get("tone_hz"):
             attempt("tone_freq", lambda: self.set_tone(rec["tone_hz"]))
             attempt("tone_on", lambda: self.set_tone_on(True))