G3.2+G3.3: classify hang/crash vs audio stall + SEH per-channel plugin crash isolation (mute channel)

native_bridge/include/NativeInstrumentEngine.h

@@ -119,6 +119,13 @@ public:
     // worker thread): real-time code drops MIDI for it. Channel-level flag —
     // survives the instance swap (the per-instance flag dies with the object).
     bool isReloading(uint32_t channel) const;
+
+    // G3.3: mark a channel whose plugin crashed inside processAudioBlock
+    // (SEH access violation). The channel is muted (real-time dispatch +
+    // renderAll skip it) until the next assign() — the plugin's state is
+    // undefined after a fault, so re-processing would fault again.
+    void markCrashed(uint32_t channel);
+    bool isCrashed(uint32_t channel) const;
     // Editor-open predicate: while any VST editor is attached, channels whose
     // plugin DLL path has an open editor count as quiet (same-plugin channels
     // too -- the worker pumps the editor's window proc inside the DLL while the
@@ -146,6 +153,8 @@ private:
     std::vector<float> scratchL_, scratchR_;
     // Channel-level reload flag (see isReloading) — indexed by MIDI channel.
     bool reloadingCh_[16] = {};
+    // G3.3: channel muted after a plugin fault inside processAudioBlock.
+    bool crashedCh_[16] = {};
     // True when the channel's plugin DLL has an attached editor (or its reload
     // is in progress): real-time code drops MIDI and skips rendering. Lowercased
     // compare inside -- Windows plugin paths are case-insensitive.