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/CLAUDE.md

@@ -1,8 +1,8 @@
-# src/core/instrument — pure VST3-instrument core (bake / engine / map / note / ui)
+# src/core/instrument — pure VST3-instrument core (bake / engine / map / note / param / ui)
 
 ## Scope
 
-The ReaSampler 9000 instrument's pure, REAPER-free, VST3-free, unit-tested core, in five
+The ReaSampler 9000 instrument's pure, REAPER-free, VST3-free, unit-tested core, in six
 subdirectories:
 
 - **`engine/`** — the polyphonic voice engine, the one set of play params, pitch shifting,