Bound the automation hold to the window the model has not caught up on, and make that authority model stated, enforced and tested

src/shell/instrument/processor_reload.cpp

@@ -153,13 +153,18 @@ std::string ReaSamplerProcessor::reloadInstrument() {
             // top of the first block after this, which is where the swap below becomes visible
             // too — so the new snapshot's first note reads it.
             sample.live = &automationLive_;
+            // BEFORE the publish: the publish is what makes the audio thread re-merge, and the
+            // merge resolves every held automation stage time against this rate. Stored after,
+            // a merge in the window between them would resolve them against the previous
+            // capture's rate — or, on the first-ever build, against 0, where secondsToFrames
+            // collapses every automated envelope stage to zero frames.
+            builtSampleRate_.store(sample.sampleRate, std::memory_order_relaxed);
             {
                 // reloadMutex_ (held for this whole function) nests livePublishMutex_ here;
                 // publishLiveParams never holds reloadMutex_, so this is the only nesting.
                 std::lock_guard<std::mutex> lp(livePublishMutex_);
                 liveParams_.publish(instrument::engine::foldLive(sample.play, sample.keyTrack));
             }
-            builtSampleRate_.store(sample.sampleRate, std::memory_order_relaxed);
             resolvedId = selId;  // the concrete pick that resolved
         }
     }