refactor(config): mirror XBPM1 layout for XBPMUSER

Rename the channels to xbpmuserc1..c4 and add the bpmuser BPM pseudo
device and the combined xbpmuser BPMDevice, as for xbpm1c*/bpm1/xbpm1.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

csaxs_bec/device_configs/bl_frontend.yaml

@@ -238,11 +238,14 @@ xbpm1:
     - bl_frontend
 
 #####################################
-#### BPMUSER quadEM (X12SA-FE-BPMUSER)
+#### XBPMUSER #######################
 #####################################
 
-bpmuser_c1:
-  description: 'BPMUSER quadEM current 1'
+# Same layout as XBPM1 above: single channels, the "bpmuser" pseudo device
+# built on them, and the combined device "xbpmuser"
+
+xbpmuserc1:
+  description: 'XBPMUSER (frontend) current 1'
   deviceClass: ophyd.EpicsSignalRO
   deviceConfig:
     read_pv: 'X12SA-FE-BPMUSER:Current1:MeanValue_RBV'
@@ -254,8 +257,8 @@ bpmuser_c1:
   deviceTags:
     - bl_frontend
 
-bpmuser_c2:
-  description: 'BPMUSER quadEM current 2'
+xbpmuserc2:
+  description: 'XBPMUSER (frontend) current 2'
   deviceClass: ophyd.EpicsSignalRO
   deviceConfig:
     read_pv: 'X12SA-FE-BPMUSER:Current2:MeanValue_RBV'
@@ -267,8 +270,8 @@ bpmuser_c2:
   deviceTags:
     - bl_frontend
 
-bpmuser_c3:
-  description: 'BPMUSER quadEM current 3'
+xbpmuserc3:
+  description: 'XBPMUSER (frontend) current 3'
   deviceClass: ophyd.EpicsSignalRO
   deviceConfig:
     read_pv: 'X12SA-FE-BPMUSER:Current3:MeanValue_RBV'
@@ -280,8 +283,8 @@ bpmuser_c3:
   deviceTags:
     - bl_frontend
 
-bpmuser_c4:
-  description: 'BPMUSER quadEM current 4'
+xbpmuserc4:
+  description: 'XBPMUSER (frontend) current 4'
   deviceClass: ophyd.EpicsSignalRO
   deviceConfig:
     read_pv: 'X12SA-FE-BPMUSER:Current4:MeanValue_RBV'
@@ -292,3 +295,37 @@ bpmuser_c4:
   softwareTrigger: false
   deviceTags:
     - bl_frontend
+
+bpmuser:
+  description: 'XBPMUSER (frontend)'
+  deviceClass: csaxs_bec.devices.pseudo_devices.bpm.BPM
+  deviceConfig:
+    left_top_ref: xbpmuserc1
+    right_top_ref: xbpmuserc2
+    right_bot_ref: xbpmuserc3
+    left_bot_ref: xbpmuserc4
+  onFailure: raise
+  enabled: true
+  readoutPriority: monitored
+  readOnly: true
+  softwareTrigger: false
+  needs:
+    - xbpmuserc1
+    - xbpmuserc2
+    - xbpmuserc3
+    - xbpmuserc4
+  deviceTags:
+    - bl_frontend
+
+xbpmuser:
+  description: 'XBPMUSER (frontend)'
+  deviceClass: csaxs_bec.devices.epics.xbpms.BPMDevice
+  deviceConfig:
+    prefix: 'X12SA-FE-BPMUSER'
+  onFailure: raise
+  enabled: true
+  readoutPriority: monitored
+  readOnly: true
+  softwareTrigger: false
+  deviceTags:
+    - bl_frontend