feat: backend servis iskeletini ve yönetim uçlarını ekle

backend/app/memory/store.py

@@ -0,0 +1,17 @@
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from app.db import MemoryItemORM
+
+
+class MemoryService:
+    def __init__(self, session: Session) -> None:
+        self.session = session
+
+    def add_item(self, content: str) -> None:
+        self.session.add(MemoryItemORM(content=content, kind="message"))
+        self.session.flush()
+
+    def latest_items(self, limit: int = 10) -> list[str]:
+        stmt = select(MemoryItemORM).order_by(MemoryItemORM.created_at.desc(), MemoryItemORM.id.desc()).limit(limit)
+        return [item.content for item in self.session.scalars(stmt)]