Close pass four: undetented host curve read, LiveValues guard, ordering assert, static-lane fix, docs

Points toPlain's exponent arm at the undetented curve map so host reads
match the editor; adds a sizeof guard plus field-poison test for
LiveValues::operator==; skips the model write when an automation value
hasn't moved; corrects five stale doc citations.

src/shell/instrument/reasampler_processor.h

@@ -190,7 +190,7 @@ public:
     // never read on the audio thread — reloadInstrument bakes it into the SampleData
     // off-thread.
     InstrumentParams instrumentParams();
-    void setInstrumentParams(const InstrumentParams& params);
+    std::uint32_t setInstrumentParams(const InstrumentParams& params);  // adopt THIS generation, never a second instrumentParamsGeneration() call
 
     // The model's edit counter, bumped by every setInstrumentParams. A holder of a COPY (the
     // editor's snapshot) re-seeds when this moves under it; the overload answers both under one
@@ -392,9 +392,9 @@ private:
     // and republishes ONLY when the RESULT moved — so neither an unchanged model nor a lane
     // resending the value it already sent reaches the per-voice fan-out. A block carrying no
     // automation and no model change costs one relaxed load plus, when the host passed a non-null
-    // IParameterChanges (REAPER's normal case), one cross-module getParameterCount(). Two blocks
-    // because the seqlock's single-writer contract is load-bearing and the two writers differ in
-    // thread; this directory's CLAUDE.md owns the argument.
+    // IParameterChanges (`[verify — DAW]` REAPER's normal case), one cross-module
+    // getParameterCount(). Two blocks because the seqlock's single-writer contract is load-bearing
+    // and the two writers differ in thread; this directory's CLAUDE.md owns the argument.
     instrument::engine::LiveParams automationLive_;
     // Audio thread only. The last liveParams_ generation merged, the last block published (the
     // republish gate compares against it), and the automation slots themselves.