feat: use assistant context as meeting memory

MeetingAssistant.Tests/MeetingSummaryInstructionBuilderTests.cs

@@ -40,6 +40,27 @@ public sealed class MeetingSummaryInstructionBuilderTests
         Assert.Contains("title parameter", instructions);
     }
 
+    [Fact]
+    public async Task DefaultPromptTreatsAssistantContextAsMeetingMemoryForUncertainty()
+    {
+        var root = Path.Combine(Path.GetTempPath(), "meeting-assistant-tests", Guid.NewGuid().ToString("N"));
+        var artifacts = CreateArtifacts(root);
+        await WriteMeetingNoteAsync(artifacts.MeetingNotePath, []);
+        var builder = new MeetingSummaryInstructionBuilder(Options.Create(new MeetingAssistantOptions
+        {
+            Agent = new AgentOptions { InitialPrompt = " " },
+            Vault = new VaultOptions { ProjectsFolder = Path.Combine(root, "Projects") }
+        }));
+
+        var instructions = await builder.BuildAsync(artifacts, CancellationToken.None);
+
+        Assert.Contains("meeting-specific memory", instructions);
+        Assert.Contains("unexpected problems", instructions);
+        Assert.Contains("missing information", instructions);
+        Assert.Contains("assumptions", instructions);
+        Assert.Contains("write_context", instructions);
+    }
+
     [Fact]
     public async Task BuilderUsesConfiguredPrompt()
     {