jfjoch_viewer: a dataset opened over HTTP keeps its source and instrument

The start message carries source_name, source_type and instrument_name, and the
broker fills all three from its config, but the HTTP reader never imported them
into the dataset's experiment - so the Inspector showed "-" for
Source / Instrument on a live connection while the same file opened from disk
showed it. Total flux and attenuator transmission, which the tooltip on that
line reports, were dropped the same way; ring current already came through.

Sample name was never affected and is unchanged.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PogHY7bWXV4bpctDPdyuDN

viewer/JFJochHttpReader.cpp

@@ -11,6 +11,7 @@
 #include "../broker/gen/model/Plots.h"
 #include "../broker/gen/model/Broker_status.h"
 #include "../broker/gen/model/Roi_definitions.h"
+#include "../common/InstrumentMetadata.h"
 #include "../common/JFJochMath.h"
 #include "../image_analysis/bragg_integration/CalcISigma.h"
 
@@ -259,9 +260,18 @@ std::shared_ptr<JFJochReaderDataset> JFJochHttpReader::UpdateDataset_i() {
 
         dataset->experiment.NumTriggers(1);
         dataset->experiment.ImagesPerTrigger(msg->start_message->number_of_images);
+
+        InstrumentMetadata instrument;
+        instrument.SourceName(msg->start_message->source_name);
+        instrument.SourceType(msg->start_message->source_type);
+        instrument.InstrumentName(msg->start_message->instrument_name);
+        dataset->experiment.ImportInstrumentMetadata(instrument);
+
         dataset->experiment.SampleName(msg->start_message->sample_name);
         dataset->experiment.SampleTemperature_K(msg->start_message->sample_temperature_K);
         dataset->experiment.RingCurrent_mA(msg->start_message->ring_current_mA);
+        dataset->experiment.TotalFlux(msg->start_message->total_flux);
+        dataset->experiment.AttenuatorTransmission(msg->start_message->attenuator_transmission);
         dataset->experiment.IncidentEnergy_keV(msg->start_message->incident_energy / 1000.0);
 
         dataset->experiment.FluorescenceSpectrum(msg->start_message->fluorescence_spectrum);