AddonContext (src/audio/addon/): engine/vstHost lifetime + snapshot rule,
the JUCE message thread with the macOS no-pump fork quarantined into ONE
file, the shutdown latch (exposed as isShuttingDown), doShutdown with a UI
teardown hook (NodeAddon points it at the editor-window nuke, #56), and the
pending-async-load registry. NodeAddon keeps using-declarations so the
binding bodies are unchanged. Also fixes SetBackingSpeed's bare `engine`
dereference — the one binding that dodged the file's own snapshot rule.
NapiHelpers (typed extractors argInt/argSlotId/argFiniteFloat/argBool/
argMidiChannel/argMidiByte) + rewrites of the unguarded bindings — the
deep-read §2 fix, done once: SetParameter/SetBypass/RemoveProcessor/
MoveProcessor/SetMultiBypass/SendMidiToSlot/SetGain plus the St-1 routing
quartet (SetPan/SetPostGain/SetBranch/SetBranchSrc). NaN slot ids no longer
coerce to slot 0; MIDI channel/program are range-checked before JUCE.
New gate: tests/napi-arg-fuzz.test.js — table-driven garbage (NaN/Inf/
negative/string/missing/object) against the real addon; chain state must be
byte-identical after the storm and a valid call must still apply.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
