class MemoryManager:
    def __init__(self, llm_engine=None):
        self.llm_engine = llm_engine
    def retrieve(self, query, top_k=5):
        return []
    async def strategic_forget(self, min_age_days=7):
        return 0
    async def compress_old_memories(self, age_days=14):
        return 0
    def stats(self):
        return {"hot": 0, "cold": 0}