Preserve recovery transcripts and add user-approved agent requests

Append successful offline recovery with a duplicate-warning marker and retain failed replay sources. Offer newly available microphones through confirmation notifications.

Add project discovery metadata and blocking association approval, plus nonblocking workflow requests that start a separate settings-agent conversation. Include regression tests, OpenSpec changes, and verified local Release startup.

MeetingAssistant/Notifications/AgentApprovalService.cs

@@ -0,0 +1,56 @@
+namespace MeetingAssistant.Notifications;
+
+public sealed record AgentApprovalPrompt(string Title, string Message, TimeSpan Timeout);
+
+public interface IAgentApprovalPromptService
+{
+    Task<bool> ConfirmAsync(AgentApprovalPrompt prompt, CancellationToken cancellationToken);
+}
+
+public sealed class NoopAgentApprovalPromptService : IAgentApprovalPromptService
+{
+    public Task<bool> ConfirmAsync(AgentApprovalPrompt prompt, CancellationToken cancellationToken) => Task.FromResult(false);
+}
+
+public sealed class AgentApprovalService
+{
+    private readonly IAgentApprovalPromptService prompts;
+    private readonly ILogger<AgentApprovalService> logger;
+    private readonly TimeSpan timeout;
+
+    public AgentApprovalService(IAgentApprovalPromptService prompts, ILogger<AgentApprovalService> logger)
+        : this(prompts, logger, TimeSpan.FromMinutes(10)) { }
+
+    internal AgentApprovalService(IAgentApprovalPromptService prompts, ILogger<AgentApprovalService> logger, TimeSpan timeout)
+    {
+        this.prompts = prompts;
+        this.logger = logger;
+        this.timeout = timeout;
+    }
+
+    public async Task<bool> ConfirmAsync(string title, string message, CancellationToken cancellationToken)
+    {
+        using var deadline = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+        deadline.CancelAfter(timeout);
+        try
+        {
+            var accepted = await prompts.ConfirmAsync(new AgentApprovalPrompt(title, message, timeout), deadline.Token)
+                .WaitAsync(deadline.Token);
+            cancellationToken.ThrowIfCancellationRequested();
+            return accepted && !deadline.IsCancellationRequested;
+        }
+        catch (OperationCanceledException) when (!cancellationToken.IsCancellationRequested)
+        {
+            return false;
+        }
+        catch (Exception exception) when (exception is not OperationCanceledException)
+        {
+            logger.LogWarning(exception, "Could not obtain user approval for {Title}", title);
+            return false;
+        }
+        finally
+        {
+            await deadline.CancelAsync();
+        }
+    }
+}