feat: optimize WebUI stream output and sanitize user-facing answers

internal/agent/orchestrator_skill_selection_test.go

@@ -93,3 +93,32 @@ func TestMatchSkillsByNameEmpty(t *testing.T) {
 		t.Fatalf("expected 0 matches, got %d", len(matched))
 	}
 }
+
+func TestSanitizeUserFacingAnswerExtractsFinalAnswer(t *testing.T) {
+	raw := "Thought: 先分析用户问题\nObservation: 已经有足够信息\nFinal Answer: 这是给用户的结果"
+	got := sanitizeUserFacingAnswer(raw)
+	if got != "这是给用户的结果" {
+		t.Fatalf("expected final answer only, got %q", got)
+	}
+}
+
+func TestSanitizeUserFacingAnswerDropsTraceLines(t *testing.T) {
+	raw := strings.Join([]string{
+		"Step 1 Thought: 检查上下文",
+		"Action: shell",
+		"Observation: ok",
+		"请执行以下变更。",
+	}, "\n")
+	got := sanitizeUserFacingAnswer(raw)
+	if got != "请执行以下变更。" {
+		t.Fatalf("expected user-facing text only, got %q", got)
+	}
+}
+
+func TestSanitizeUserFacingAnswerKeepsNormalAnswer(t *testing.T) {
+	raw := "1. 先打开配置文件\n2. 修改端口后重启服务"
+	got := sanitizeUserFacingAnswer(raw)
+	if got != raw {
+		t.Fatalf("expected answer unchanged, got %q", got)
+	}
+}