Add inactivity safeguard and speaker diagnostics

MeetingAssistant/Recording/IMeetingInactivityClock.cs

@@ -0,0 +1,18 @@
+namespace MeetingAssistant.Recording;
+
+public interface IMeetingInactivityClock
+{
+    DateTimeOffset Now { get; }
+
+    Task DelayAsync(TimeSpan delay, CancellationToken cancellationToken);
+}
+
+public sealed class SystemMeetingInactivityClock : IMeetingInactivityClock
+{
+    public DateTimeOffset Now => DateTimeOffset.Now;
+
+    public Task DelayAsync(TimeSpan delay, CancellationToken cancellationToken)
+    {
+        return Task.Delay(delay, cancellationToken);
+    }
+}