Live stills: the analysis keeps its own copy of the experiment; a failed end message fill sends the end message without the results

StillsGPUAnalysis held the DiffractionExperiment it was given by reference, and
JFJochReceiverRugnuxStills::OnStart gave it a local (the experiment with the goniometer
removed for force_still), which went at the end of OnStart while the pre-pass, analysis
and merge threads and every checkpoint merge went on reading it. Seen as std::bad_alloc
and heap corruption in a second stills run after a failed one. The member is now a copy.

AddToEndMessage of the stills receiver catches a failure of FillEndMessage as the
rotation receiver does: the end message goes out without the analysis results instead
of not at all.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HVeDQsU5a8AJUdJPgWevAK

receiver/JFJochReceiverRugnuxStills.cpp

@@ -9,6 +9,7 @@
 #include "../common/time_utc.h"
 #include "../frame_serialize/CBORStream2Serializer.h"
 #include "../rugnux/RugnuxDefaults.h"
+#include "RugnuxStructure.h"
 
 JFJochReceiverRugnuxStills::JFJochReceiverRugnuxStills(const DiffractionExperiment &in_experiment,
                                                          const PixelMask &in_pixel_mask,
@@ -216,8 +217,14 @@ void JFJochReceiverRugnuxStills::SendAnalysedImage(DataMessage &message, const A
 
 void JFJochReceiverRugnuxStills::AddToEndMessage(EndMessage &message) {
     JFJochReceiverStream::AddToEndMessage(message);
-    if (stills)
-        stills->FillEndMessage(message);
+    // A failure here costs the end message the analysis only: it goes out as the receiver made it.
+    try {
+        if (stills)
+            stills->FillEndMessage(message);
+    } catch (const std::exception &e) {
+        logger.Error("rugnux live: the end message goes without the analysis results - {}", e.what());
+        DropResultBlocks(message);
+    }
 }
 
 void JFJochReceiverRugnuxStills::Cut(const std::string &reason) {

receiver/StillsGPUAnalysis.h

@@ -88,7 +88,7 @@ public:
     void FillEndMessage(EndMessage &message) const;
 
 private:
-    const DiffractionExperiment &experiment;
+    const DiffractionExperiment experiment;
     const PixelMask &mask;
     const StartMessage start;
     IndexerThreadPool *indexing_thread_pool;