fix(processor): close S-VIEW-4 previewVelocity persistence loop

Add previewVelocity_ member to ReaSamplerProcessor; populate it in
getState and restore it in setState so the field round-trips in the
plugin, not just in the pure unit test. Clamp 1..127 at the
deserialize read boundary in sample_map.cpp.

src/vst/reasampler_processor.cpp

@@ -197,6 +197,9 @@ tresult PLUGIN_API ReaSamplerProcessor::setState(IBStream* state) {
         channelMode_ = cs.channelMode;
     }
     applyOutputArrangement(cs.channelMode);
+    // S-VIEW-4: restore the per-instance preview velocity. No mutex — setState is a load-time
+    // call serialized by the host; there is no concurrent writer before Wave 2.
+    previewVelocity_ = cs.previewVelocity;
     // Rebuild from the restored state (off-thread — setState is a load-time call).
     reloadFromBank();
     return kResultOk;
@@ -217,6 +220,7 @@ tresult PLUGIN_API ReaSamplerProcessor::getState(IBStream* state) {
         std::lock_guard<std::mutex> lock(assignMarkerMutex_);
         state_out.lastConsumedAssignGeneration = lastConsumedAssignGeneration_;  // S8 reader marker
     }
+    state_out.previewVelocity = previewVelocity_;  // S-VIEW-4: persist the preview strike velocity
     const std::vector<std::uint8_t> bytes = serializeComponentState(state_out);
     if (!bytes.empty()) {
         const tresult wr = state->write(const_cast<std::uint8_t*>(bytes.data()),