Harden panic recovery and service shutdown

bitchat/ViewModels/VoiceRecordingViewModel.swift

@@ -188,8 +188,25 @@ final class VoiceRecordingViewModel: ObservableObject {
 
         Task {
             let finalDuration = Date().timeIntervalSince(startDate)
-            if let url = await session.finish(),
-               isValidRecording(at: url, duration: finalDuration) {
+            if let url = await session.finish() {
+                // Panic and a newer hold both invalidate this completion.
+                // Never route an old recording using a post-panic target.
+                guard generation == holdGeneration else {
+                    try? FileManager.default.removeItem(at: url)
+                    return
+                }
+                guard isValidRecording(
+                    at: url,
+                    duration: finalDuration
+                ) else {
+                    guard state == .idle else { return }
+                    state = .error(
+                        message: finalDuration < VoiceRecorder.minRecordingDuration
+                        ? "Recording is too short."
+                        : "Recording failed to save."
+                    )
+                    return
+                }
                 completion(url)
             } else {
                 guard generation == holdGeneration, state == .idle else { return }
@@ -206,6 +223,17 @@ final class VoiceRecordingViewModel: ObservableObject {
         finish(completion: nil)
     }
 
+    /// Invalidates in-flight permission/start/finalize callbacks and tears
+    /// down an active microphone before the panic transaction continues.
+    func panicWipe() {
+        holdGeneration &+= 1
+        let session = activeSession
+        activeSession = nil
+        state = .idle
+        isLiveStreaming = false
+        session?.panicCancelSynchronously()
+    }
+
     private func isValidRecording(at url: URL, duration: TimeInterval) -> Bool {
         if let attributes = try? FileManager.default.attributesOfItem(atPath: url.path),
            let fileSize = attributes[.size] as? NSNumber,