Fix handle 58 second timeout with full engine restart to prevent teleprompter freeze

[G10Bi]

Problem

After ~58 seconds of continuous speech recognition, SFSpeechRecognizer hits
its internal timeout (error 1110 / 216) and the teleprompter freezes permanently.

The original code called restartTask() — a soft restart that reuses the existing
AVAudioEngine. But macOS also pauses the microphone hardware during these
timeouts. The engine's internal state becomes unrecoverable, and no amount of
task-level restart can bring it back. The only way out was a manual stop/start.

Root cause

AVAudioEngine caches the audio device format internally. After the system pauses
the mic (triggered by the 58s speech recognition limit), the cached format is
invalidated but the engine doesn't detect this. A soft restart (restartTask())
only recreates the SFSpeechRecognitionTask, not the engine. The new task receives
silence or corrupt buffers and fails silently.

Solution

Added forceRestartAfterTimeout() — a method that performs a complete teardown
and recreation of the entire audio stack:

private func forceRestartAfterTimeout() {
    // 1. Save state
    let savedOffset = recognizedCharCount
    let savedSource = sourceText
    
    // 2. Full cleanup (task + engine + tap)
    cleanupRecognition()
    
    // 3. Fresh engine — picks up current hardware format
    audioEngine = AVAudioEngine()
    
    // 4. Restore state
    sourceText = savedSource
    recognizedCharCount = savedOffset
    matchStartOffset = savedOffset
    
    // 5. Restart after short delay for resource release
    DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
        self.beginRecognition()
    }
}