feat: add shared fund quote capability

app/infrastructure/fund_quote_cache.py

@@ -0,0 +1,22 @@
+"""基金行情短缓存适配器。缓存失败只影响性能，不阻塞外部行情查询。"""
+
+from typing import Protocol
+
+from app.infrastructure.memory_cache import CacheReadResult
+
+
+class FundQuoteCacheClient(Protocol):
+    async def get(self, key: str) -> CacheReadResult: ...
+
+    async def set(self, key: str, value: str, ttl_seconds: int) -> bool: ...
+
+
+class FundQuoteCache:
+    def __init__(self, client: FundQuoteCacheClient) -> None:
+        self.client = client
+
+    async def get(self, key: str) -> CacheReadResult:
+        return await self.client.get(key)
+
+    async def set(self, key: str, value: str, ttl_seconds: int) -> bool:
+        return await self.client.set(key, value, ttl_seconds)