fix(go): exclude reasoning part when return value from Text() function

Author: jcooky

go/ai/generate.go

@@ -768,7 +768,9 @@ func (c *ModelResponseChunk) Text() string {
 	}
 	var sb strings.Builder
 	for _, p := range c.Content {
-		sb.WriteString(p.Text)
+		if p.IsText() || p.IsData() {
+			sb.WriteString(p.Text)
+		}
 	}
 	return sb.String()
 }
@@ -787,7 +789,9 @@ func (m *Message) Text() string {
 	}
 	var sb strings.Builder
 	for _, p := range m.Content {
-		sb.WriteString(p.Text)
+		if p.IsText() || p.IsData() {
+			sb.WriteString(p.Text)
+		}
 	}
 	return sb.String()
 }