feat: add natural elder story companion flow

internal/orchestration/validation_test.go

@@ -78,28 +78,47 @@ func TestBuildContextSummaryIncludesContinuityAndBoundariesWithinSnapshotLimit(t
 		Background: "退休教师", Interests: []string{"戏曲"}, ConversationGoal: "自然陪伴", Pace: "slow",
 		PreferredTopics: []string{"家乡"}, AvoidedTopics: []string{"收入", "家庭矛盾"},
 	}
-	result := buildContextSummary("王阿姨", profile,
-		[]string{"上次聊到刚刚注册了个体工商户，准备开始新的工作。"},
+	result := buildCompanionContextSummary("王阿姨", profile,
+		[]recentConversationContext{{Summary: "上次聊到刚刚注册了个体工商户，准备开始新的工作。", OpenTopic: "如果她愿意，可以聊聊开始新工作后最期待的事。"}},
 		[]string{"喜欢在周末听越剧。"})
-	for _, expected := range []string{"交流边界", "收入", "王阿姨", "本次交流目标：自然陪伴", "交流节奏：放慢语速", "优先话题：家乡", "背景资料：退休教师", "兴趣：戏曲", "最近第1次通话摘要", "注册了个体工商户", "已人工确认的长期记忆", "越剧"} {
+	for _, expected := range []string{"交流边界", "收入", "王阿姨", "历史资料仅作背景", "先回应长者当前说的话", "可选续聊线索", "最期待的事", "本次交流目标：自然陪伴", "交流节奏：放慢语速", "优先话题：家乡", "背景资料：退休教师", "兴趣：戏曲", "最近第1次通话摘要", "注册了个体工商户", "已确认的长期记忆", "越剧"} {
 		if !strings.Contains(result, expected) {
 			t.Fatalf("context %q does not contain %q", result, expected)
 		}
 	}
-	oversized := buildContextSummary(strings.Repeat("长", 120), authorizedSubjectContext{
+	oversized := buildCompanionContextSummary(strings.Repeat("长", 120), authorizedSubjectContext{
 		Background: strings.Repeat("背", 500), AvoidedTopics: []string{strings.Repeat("禁", 50), "家庭矛盾"},
 		PreferredTopics: []string{strings.Repeat("优", 50)}, Interests: []string{strings.Repeat("兴", 50)},
-	}, []string{strings.Repeat("摘", 500), "第二次摘要", "第三次摘要"}, []string{strings.Repeat("忆", 500), "第二条记忆", "第三条记忆", "第四条记忆", "第五条记忆"})
+	}, []recentConversationContext{
+		{Summary: strings.Repeat("摘", 500), OpenTopic: strings.Repeat("续", 500)},
+		{Summary: "第二次摘要", OpenTopic: "较旧的续聊线索"},
+		{Summary: "第三次摘要"},
+	}, []string{strings.Repeat("忆", 500), "第二条记忆", "第三条记忆"})
 	if len([]rune(oversized)) > contextSummaryLimit {
 		t.Fatalf("context length=%d exceeds snapshot budget", len([]rune(oversized)))
 	}
-	for _, expected := range []string{"交流边界", "家庭矛盾", "最近第3次通话摘要", "第三次摘要", "已人工确认的长期记忆", "第五条记忆"} {
+	for _, expected := range []string{"交流边界", "家庭矛盾", "可选续聊线索", strings.Repeat("续", 20), "最近第3次通话摘要", "第三次摘要", "已确认的长期记忆"} {
 		if !strings.Contains(oversized, expected) {
 			t.Fatalf("oversized context %q lost priority field %q", oversized, expected)
 		}
 	}
 }
 
+func TestCompanionContextUsesOnlyNewestAvailableOpenTopic(t *testing.T) {
+	recent := []recentConversationContext{
+		{Summary: "最近一次只聊了天气。"},
+		{Summary: "上一次谈到老同事。", OpenTopic: "有机会可以聊聊最难忘的一位老同事。"},
+		{Summary: "更早谈到家乡。", OpenTopic: "可以聊聊家乡。"},
+	}
+	if got := suggestedOpenTopic(recent); got != "有机会可以聊聊最难忘的一位老同事。" {
+		t.Fatalf("selected open topic=%q", got)
+	}
+	result := buildCompanionContextSummary("李叔叔", authorizedSubjectContext{}, recent, nil)
+	if strings.Count(result, "可选续聊线索") != 1 || strings.Contains(result, "可以聊聊家乡") {
+		t.Fatalf("context exposed multiple continuation cues: %q", result)
+	}
+}
+
 func TestConversationContinuityRequiresBothExplicitConsents(t *testing.T) {
 	for _, test := range []struct {
 		value json.RawMessage