Add conversation transcription samples with speaker diarization for C#

[TheMysteriousStranger90]

Summary

Add C# samples for real-time conversation transcription with speaker diarization using ConversationTranscriber API.

What's added

• New file: conversation_transcription_samples.cs with 4 sample methods:
  1. Conversation transcription from microphone
  2. Conversation transcription from WAV file
  3. Conversation transcription with specified language
  4. Conversation transcription with push audio stream
• Updated Program.cs with menu entry for the new samples
• Updated both .csproj files to include the new source file

Motivation

The samples/csharp/ console application includes SpeechRecognizer samples (no speaker identification)
and RemoteMeetingSamples (complex async meeting API), but has no ConversationTranscriber examples.
While a basic quickstart exists in quickstart/csharp/dotnet/conversation-transcription/ (single file-input
scenario), the main samples console app lacks coverage of this API. This PR adds 4 common scenarios
(microphone, WAV file, language selection, push stream) with automatic speaker diarization (Guest-1, Guest-2, etc.)
directly into the samples console app menu.

Tested

• All 4 methods tested with Speech SDK 1.48.1
• Microphone methods correctly identify multiple speakers in real-time
• File and push stream methods work with existing sample WAV files

[Copilot]

Pull request overview

Adds new C# console-app samples demonstrating real-time conversation transcription with speaker diarization via the ConversationTranscriber API, and wires them into the existing sample menu.

Changes:

• Added ConversationTranscriptionSamples with 4 conversation transcription scenarios (mic, WAV file, language selection, push stream).
• Added a new main-menu entry and submenu in Program.cs to invoke the new samples.
• Updated both console .csproj files to compile/link the new shared sample source.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
samples/csharp/sharedcontent/console/Program.cs	Adds a new top-level menu option and submenu to run the conversation transcription samples.
samples/csharp/sharedcontent/console/conversation_transcription_samples.cs	Introduces 4 new ConversationTranscriber sample methods, including microphone, file, language, and push-stream scenarios.
samples/csharp/dotnetcore/console/samples/samples.csproj	Links the new shared sample source file into the .NET (net8.0) console project.
samples/csharp/dotnet-windows/console/samples/samples.csproj	Links the new shared sample source file into the .NET Framework (net462) console project.

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[Copilot]

This sample uses SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion"), but the rest of the console samples consistently use SpeechConfig.FromEndpoint(new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"), "YourSubscriptionKey") (e.g., sharedcontent/console/speech_recognition_samples.cs:28). Consider switching to FromEndpoint here as well so developers can copy/paste the same credential pattern across samples.

Suggested change

	var config = SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion");
	var config = SpeechConfig.FromEndpoint(new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"), "YourSubscriptionKey");

[Copilot]

This sample uses SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion"), but the rest of the console samples consistently use SpeechConfig.FromEndpoint(new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"), "YourSubscriptionKey") (e.g., sharedcontent/console/speech_recognition_samples.cs:28). Consider switching to FromEndpoint here as well so developers can copy/paste the same credential pattern across samples.

Suggested change

	// Creates an instance of a speech config with specified subscription key and region.
	// Replace with your own subscription key and service region (e.g., "westus").
	var config = SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion");
	// Creates an instance of a speech config with the specified endpoint and subscription key.
	// Replace with your own endpoint (e.g., "https://westus.api.cognitive.microsoft.com") and subscription key.
	var config = SpeechConfig.FromEndpoint(new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"), "YourSubscriptionKey");

[Copilot]

This sample uses SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion"), but the rest of the console samples consistently use SpeechConfig.FromEndpoint(new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"), "YourSubscriptionKey") (e.g., sharedcontent/console/speech_recognition_samples.cs:28). Consider switching to FromEndpoint here as well so developers can copy/paste the same credential pattern across samples.

Suggested change

	// Creates an instance of a speech config with specified subscription key and region.
	// Replace with your own subscription key and service region (e.g., "westus").
	var config = SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion");
	// Creates an instance of a speech config with specified endpoint and subscription key.
	// Replace with your own endpoint (e.g., "https://westus.api.cognitive.microsoft.com") and subscription key.
	var config = SpeechConfig.FromEndpoint(new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"), "YourSubscriptionKey");

[Copilot]

This sample uses SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion"), but the rest of the console samples consistently use SpeechConfig.FromEndpoint(new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"), "YourSubscriptionKey") (e.g., sharedcontent/console/speech_recognition_samples.cs:28). Consider switching to FromEndpoint here as well so developers can copy/paste the same credential pattern across samples.

Suggested change

	// Creates an instance of a speech config with specified subscription key and region.
	// Replace with your own subscription key and service region (e.g., "westus").
	var config = SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion");
	// Creates an instance of a speech config with specified endpoint and subscription key.
	// Replace with your own endpoint and subscription key.
	var config = SpeechConfig.FromEndpoint(
	new Uri("https://YourServiceRegion.api.cognitive.microsoft.com"),
	"YourSubscriptionKey");

[Copilot]

Task.Run(() => Console.ReadKey()) is started here but never cancelled if stopRecognition.Task completes first (e.g., on cancellation/session stop). That background ReadKey can consume the next keypress intended for the menu, leading to confusing input behavior. Consider using a synchronous Console.ReadKey() stop mechanism (like other samples) or restructure with a key task that is safely drained/ignored without leaving a pending read on the console input buffer.

Suggested change

	// Waits for completion. Use Task.WaitAny to keep the task rooted.
	Task.WaitAny(new Task[] { stopRecognition.Task, Task.Run(() => Console.ReadKey()) });
	// Waits for completion without leaving a background Console.ReadKey pending.
	while (!stopRecognition.Task.IsCompleted)
	{
	if (Console.KeyAvailable)
	{
	Console.ReadKey(true);
	break;
	}
	await Task.WhenAny(stopRecognition.Task, Task.Delay(100)).ConfigureAwait(false);
	}

[Copilot]

Task.Run(() => Console.ReadKey()) is started here but never cancelled if stopRecognition.Task completes first (e.g., on cancellation/session stop). That background ReadKey can consume the next keypress intended for the menu, leading to confusing input behavior. Consider using a synchronous Console.ReadKey() stop mechanism (like other samples) or restructure with a key task that is safely drained/ignored without leaving a pending read on the console input buffer.

Suggested change

	Task.WaitAny(new Task[] { stopRecognition.Task, Task.Run(() => Console.ReadKey()) });
	while (!stopRecognition.Task.IsCompleted)
	{
	if (Console.KeyAvailable)
	{
	Console.ReadKey(true);
	break;
	}
	await Task.Delay(50).ConfigureAwait(false);
	}