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

src-tauri/Cargo.toml

@@ -23,6 +23,7 @@ windows-sys = { version = "0.59", features = [
   "Win32_Foundation",
   "Win32_Security",
   "Win32_System_Memory",
+  "Win32_System_Threading",
 ] }
 
 [profile.release]

src-tauri/src/lib.rs

@@ -95,6 +95,21 @@ fn kill_process_tree(child: &CommandChild) -> bool {
         .unwrap_or(false)
 }
 
+/// G3.2: true if a process with `pid` still exists (OpenProcess + exit code).
+/// Used to classify a stalled heartbeat: pid alive = HANG, pid gone = CRASH.
+fn process_alive(pid: u32) -> bool {
+    use windows_sys::Win32::Foundation::STILL_ACTIVE;
+    use windows_sys::Win32::System::Threading::{GetExitCodeProcess, OpenProcess};
+    let handle = unsafe { OpenProcess(windows_sys::Win32::System::Threading::PROCESS_QUERY_LIMITED_INFORMATION, 0, pid) };
+    if handle.is_null() {
+        return false; // not found or no access -> treat as gone
+    }
+    let mut code: u32 = 0;
+    let ok = unsafe { GetExitCodeProcess(handle, &mut code) } != 0;
+    unsafe { windows_sys::Win32::Foundation::CloseHandle(handle) };
+    ok && code == STILL_ACTIVE as u32
+}
+
 /// Audio frame pushed to the WebView (bridge SHM -> `bridge-audio` event).
 #[derive(Clone, serde::Serialize)]
 struct AudioFrame {
@@ -478,8 +493,24 @@ pub fn run() {
                             let log_dir = std::env::var("APPDATA").unwrap_or_else(|_| ".".into());
                             let log_path = std::path::Path::new(&log_dir)
                                 .join("SonicForgeDAW").join("logs").join("spawn.log");
-                            let mut line = String::from("[tauri] bridge heartbeat stalled 3s — restart attempt #1
-");
+                            // G3.2: phân loại stall — process còn sống = HANG
+                            // (heartbeat thread kẹt), pid biến mất = CRASH.
+                            let pid = pump_handle
+                                .state::<BridgeProcess>()
+                                .0
+                                .lock()
+                                .ok()
+                                .and_then(|g| g.as_ref().map(|c| c.pid()));
+                            let kind = match pid {
+                                Some(p) if process_alive(p) => {
+                                    format!("HUNG (pid {p} alive, heartbeat stalled)")
+                                }
+                                Some(p) => format!("CRASHED (pid {p} gone)"),
+                                None => "UNKNOWN (no tracked pid)".into(),
+                            };
+                            let mut line = format!(
+                                "[tauri] bridge heartbeat stalled 3s — {kind} — restart attempt #1\n"
+                            );
                             // FIX: kill bridge cũ trước — không được để 2 bridge
                             // cùng map SHM (race control queue / double load).
                             kill_bridge(&pump_handle);