ci: consolidate platform pipelines and test prerequisites on macOS support

MeetingAssistant/MacOs/MacOsAgentApprovalPromptService.cs

@@ -0,0 +1,23 @@
+using MeetingAssistant.Notifications;
+
+namespace MeetingAssistant.MacOs;
+
+public sealed class MacOsAgentApprovalPromptService(DesktopUserRequestStore requests) : IAgentApprovalPromptService
+{
+    public async Task<bool> ConfirmAsync(AgentApprovalPrompt prompt, CancellationToken cancellationToken)
+    {
+        var request = requests.Add(new DesktopUserRequestSpec(
+            "agent-approval", prompt.Title, prompt.Message, prompt.Timeout,
+            [new("yes", "Yes"), new("no", "No")]), cancellationToken);
+        try
+        {
+            var response = await request.Decision.WaitAsync(cancellationToken);
+            cancellationToken.ThrowIfCancellationRequested();
+            return response == "yes";
+        }
+        finally
+        {
+            requests.Dismiss(request.Id);
+        }
+    }
+}