s12: thread project rate through v3 legacy lift; remove 44100 literals

kLegacyV3NominalRate removed. readZonesPayload, deserializePerformance, deserializeComponentState now take a projectRate for v3 frames→seconds. Rate fields default 0 (invalid). Four 44100 fallbacks replaced with assert+safe-return. 96k v3-lift test added.

src/vst/reasampler_processor.cpp

@@ -176,7 +176,11 @@ tresult PLUGIN_API ReaSamplerProcessor::setState(IBStream* state) {
     // blob restores {"", zones}; a v1 S4 single-selection blob restores {id, one-zone map} so
     // the old pick survives as both; an empty/unknown blob restores {"", no zones} — the S10
     // silent empty state (no first-sample fallback in reloadFromBank).
-    const ComponentState cs = deserializeComponentState(bytes);
+    // Pass sampleRate_ as the project rate for legacy v3 blob conversion (frames -> seconds at
+    // the v3 read boundary). sampleRate_ is set by setupProcessing; REAPER calls setupProcessing
+    // before setState on project load, so sampleRate_ is the real host rate here. A v3 blob on a
+    // pre-setup call would assert inside readZonesPayload (a programming error, not a field case).
+    const ComponentState cs = deserializeComponentState(bytes, sampleRate_);
     setSelectedSampleId(cs.selectionId);
     setPerformanceMap(cs.map);
     // S8: restore the last-consumed assignment generation so a re-open does not re-apply a