Merge branch 'refactor/backend-architecture' into development

api/app/features/memory/service.py

@@ -0,0 +1,23 @@
+"""
+MemoryService — conversation / memoir 的统一门面。
+一期先实现基础接口签名，具体逻辑后续补充。
+"""
+from sqlalchemy.ext.asyncio import AsyncSession
+
+
+class MemoryService:
+    def __init__(self, db: AsyncSession):
+        self._db = db
+
+    async def ingest_transcript(self, user_id: str, conversation_id: str, transcript: str) -> str:
+        """Ingest conversation transcript into memory. Returns source_id."""
+        raise NotImplementedError("Phase 2+ implementation")
+
+    async def retrieve(self, user_id: str, query: str, *, top_k: int = 10) -> dict:
+        """Retrieve relevant evidence for a query. 一期返回空结构，二期接入混合检索。"""
+        return {
+            "relevant_chunks": [],
+            "relevant_summaries": [],
+            "relevant_facts": [],
+            "timeline_hints": [],
+        }