enhance: trim blocking code markdown identifier in AI response

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/AI/Agent.cs

@@ -46,9 +46,28 @@ public async Task GenerateCommitMessageAsync(string repo, string changeList, Act
                             onUpdate.Invoke(string.Empty);
                             onUpdate.Invoke("# Assistant");
                             if (completion.Content.Count > 0)
-                                onUpdate.Invoke(completion.Content[0].Text);
+                            {
+                                var text = completion.Content[0].Text.ReplaceLineEndings("\n").Trim();
+                                var start = 0;
+                                var len = text.Length;
+                                if (text.StartsWith("```\n", StringComparison.Ordinal))
+                                {
+                                    start += 4;
+                                    len -= 4;
+                                }
+
+                                if (text.EndsWith("\n```", StringComparison.Ordinal))
+                                    len -= 4;
+
+                                if (len > 0)
+                                    onUpdate.Invoke(text.Substring(start, len));
+                                else
+                                    onUpdate.Invoke("[No content was generated.]");
+                            }
                             else
+                            {
                                 onUpdate.Invoke("[No content was generated.]");
+                            }
 
                             onUpdate.Invoke(string.Empty);
                             onUpdate.Invoke("# Token Usage");