feat(omny): interferometer channels after the OMNY interferometer rework (Zygo 4004 only, flOMNI order: ST FZP Y, ST FZP X, RotZ, RotX); laser-tracker check on ssi_2; mirror table marked TODO

Loop side: OMNY branch zygo-4004 (RT_sampler / server formats unchanged).
To be tested as one package with the loop after the recabling.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M8zoDvEVcT4jbFjSNU9Rii

csaxs_bec/devices/omny/rt/rt_omny_ophyd.py

@@ -108,6 +108,10 @@ class RtOMNYController(Controller):
         self.ssi = {}
         self._min_scan_buffer_reached = False
         self.switchbox_socket = socket.socket()
+        # TODO (OMNY interferometer rework 2026-11-05, branch zygo-4004): the signal channels changed meaning -
+        # ssi_1 ST FZP Y, ssi_2 ST FZP X, ssi_3 RotZ, ssi_4 RotX, ssi_5 not read (before: ssi_1 OSA FZP Y, ssi_2 ST OSA Y,
+        # ssi_3 OSA FZP X, ssi_4 ST OSA X, ssi_5 Angle). The mirror list below is still the one before the rework; which
+        # mirrors remain and on which channel each is optimized is to be defined by Mirko (OMNY docs/feedback_report.md).
         self.mirror_parameters = {
             1: {
                 "opt_signalchannel": "ssi_5",
@@ -284,8 +288,9 @@ class RtOMNYController(Controller):
             return
         # first check on target
         self.laser_tracker_wait_on_target()
-        # when on target, check interferometer signal
-        signal = self._omny_interferometer_get_signalsample("ssi_4", 0.1)
+        # when on target, check interferometer signal (ssi_2 = ST FZP X since the interferometer rework 2026-11-05;
+        # was ssi_4 = ST OSA X)
+        signal = self._omny_interferometer_get_signalsample("ssi_2", 0.1)
         rtx = self.device_manager.devices.rtx
         min_signal = rtx.user_parameter.get("min_signal")
         low_signal = rtx.user_parameter.get("low_signal")
@@ -297,7 +302,7 @@ class RtOMNYController(Controller):
 
             wait_counter += 1
             time.sleep(0.2)
-            signal = self._omny_interferometer_get_signalsample("ssi_4", 0.1)
+            signal = self._omny_interferometer_get_signalsample("ssi_2", 0.1)
 
         if signal < low_signal:
             print(
@@ -749,7 +754,9 @@ class RtOMNYController(Controller):
             print(f"Galil Trackcounters y={trackyct}, z={trackzct}")
 
     def show_signal_strength_interferometer(self):
-        channelnames = {1: "OSA FZP Y", 2: "ST OSA Y", 3: "OSA FZP X", 4: "ST OSA X", 5: "Angle"}
+        # Zygo 4004 only in the flOMNI channel order since the OMNY interferometer rework (OMNY branch zygo-4004,
+        # 2026-11-05); before: 1 OSA FZP Y, 2 ST OSA Y, 3 OSA FZP X, 4 ST OSA X, 5 Angle (2402 card)
+        channelnames = {1: "ST FZP Y", 2: "ST FZP X", 3: "RotZ", 4: "RotX", 5: "(2402 not read)"}
         self.feedback_get_status_and_ssi()
         t = PrettyTable()
         t.title = f"Interferometer signal strength"