Expose NDI discovery error details

servers/unraid/tail2-pose-server/app/tail2/ndi.py

@@ -36,7 +36,7 @@ class NDIReceiver(threading.Thread):
             except Exception as exc:
                 self.state.ndi_connected = False
                 self.state.error_code = "NDI_DISCONNECTED"
-                LOG.warning("NDI receive session ended: %s", type(exc).__name__)
+                LOG.warning("NDI receive session ended: %s: %s", type(exc).__name__, str(exc)[:300])
             self.stop_event.wait(2.0)
 
     def _receive_session(self) -> None:
@@ -66,7 +66,7 @@ class NDIReceiver(threading.Thread):
                     source = finder.get_source(self.source_name)
                     break
             if source is None:
-                raise RuntimeError("configured NDI source not discovered")
+                raise RuntimeError(f"configured NDI source not discovered; last_sources={names}")
             receiver = Receiver(color_format=RecvColorFormat.BGRX_BGRA,
                                 bandwidth=RecvBandwidth.highest)
             video = VideoFrameSync()
@@ -94,4 +94,3 @@ class NDIReceiver(threading.Thread):
             if receiver is not None and receiver.is_connected():
                 receiver.disconnect()
             finder.close()
-