feat(api): 收敛对话与记忆流程边界，引入 LLM 网关与专用服务

- MemoryService 异步路径委托 MemoryIngestService / MemoryRetrievalService；富化派发经 MemoryEnrichmentScheduler
- WebSocket pipeline 经 ChatTurnService 与显式 DTO 编排单轮对话；回忆录片段入队由 MemoirIngestScheduler 封装
- 新增 LlmGateway（LlmUseCase），各 agent、任务与适配器对齐 ports
- 补充 memory 提示适配、runtime 类型、memory-retrieval 文档、ai-touchpoints 说明与扫描脚本及配套测试

Made-with: Cursor

api/tests/test_memoir_ingest_scheduler.py

@@ -0,0 +1,65 @@
+from __future__ import annotations
+
+import pytest
+
+from app.features.memoir.ingest_scheduler import MemoirIngestScheduler
+
+
+class _FakeRunner:
+    def __init__(self) -> None:
+        self.queued: list[tuple[str, str, int]] = []
+        self.flushed: list[tuple[str, list[str]]] = []
+
+    async def queue_message(
+        self,
+        user_id: str,
+        segment_id: str,
+        *,
+        text_char_count: int = 0,
+    ) -> None:
+        self.queued.append((user_id, segment_id, text_char_count))
+
+    async def flush_pending(
+        self,
+        user_id: str,
+        *,
+        extra_segment_ids: list[str] | None = None,
+    ) -> str:
+        self.flushed.append((user_id, list(extra_segment_ids or [])))
+        return "task-1"
+
+
+@pytest.mark.asyncio
+async def test_queue_segment_returns_visible_phase_plan() -> None:
+    runner = _FakeRunner()
+    scheduler = MemoirIngestScheduler(runner=runner)
+
+    plan = await scheduler.queue_segment(
+        "user-1",
+        "seg-1",
+        text_char_count=42,
+        trigger="evaluation_replay",
+    )
+
+    assert runner.queued == [("user-1", "seg-1", 42)]
+    assert plan.user_id == "user-1"
+    assert plan.segment_ids == ("seg-1",)
+    assert plan.trigger == "evaluation_replay"
+
+
+@pytest.mark.asyncio
+async def test_flush_pending_returns_plan_and_task_id() -> None:
+    runner = _FakeRunner()
+    scheduler = MemoirIngestScheduler(runner=runner)
+
+    plan, task_id = await scheduler.flush_pending(
+        "user-1",
+        extra_segment_ids=["seg-1", "seg-2"],
+        trigger="conversation_end",
+    )
+
+    assert runner.flushed == [("user-1", ["seg-1", "seg-2"])]
+    assert task_id == "task-1"
+    assert plan.user_id == "user-1"
+    assert plan.segment_ids == ("seg-1", "seg-2")
+    assert plan.trigger == "conversation_end"