Service both VST3 parameter channels, and promote pitch key-track and Trigger length so all 44 ids issue

The SDK's own single-component sample drains inputParameterChanges in
process() and implements setParamNormalized; automation was reading the
GUI channel alone. The audio thread now patches a block it solely owns.

src/core/instrument/param/param_live.h

@@ -0,0 +1,29 @@
+// param_live.h — the AUDIO-THREAD half of a host parameter write: one exposed control patched
+// into the live block, in place, with no allocation and no lock. It exists because the model
+// layer cannot run on the audio thread (PlaySeconds carries velocity curves and spline contours,
+// so resolvePlay allocates), while `IParameterChanges` is delivered there.
+
+#pragma once
+
+#include "core/instrument/engine/live_params.h"
+#include "core/instrument/ui/deck_groups.h"  // DeckParam
+
+namespace reasampler::instrument::param {
+
+using ui::DeckParam;
+
+// Writes `normalized` for `deck` into `block`. RT-SAFE: no allocation, no lock, no transcendental
+// beyond the taper's own. Returns false for a control this block does not carry — master gain,
+// which reaches the audio as the processor's own atomic, and anything unexposed.
+//
+// The value laws are NOT restated here: `ui::storedFromNorm` is the same norm -> stored map
+// `setDeckParam` writes with, and `map::secondsToFrames` the same fold `resolvePlay` uses. What
+// IS new is the routing — which member of the block a control names — and that is pinned by an
+// exhaustive equivalence test against the model path over every exposed control, rather than by
+// two tables that happen to agree.
+//
+// `sampleRate` is the rate the loaded capture was BUILT at (the processor's builtSampleRate_),
+// so a patched stage time lands on exactly the frames the build would have resolved.
+bool applyLiveParam(engine::LiveValues& block, DeckParam deck, double normalized, int sampleRate);
+
+}  // namespace reasampler::instrument::param