feat: 数据采集健壮性改进

- 新增 src/core/retry.py: 指数退避 + 抖动的重试装饰器
- bzzoiro: 改进重试逻辑
  - 429/5xx/网络错误均触发指数退避重试
  - 4xx 直接抛(不重试)
- understat: 新增重试(原无重试)
- injuries: 新增重试 + 文件缓存 7 天过期
- sources.py: 延迟导入修复循环导入

src/data/bzzoiro.py

@@ -7,6 +7,7 @@ from __future__ import annotations
 import asyncio
 import json as _json
 import logging
+import random
 import time as _time
 import urllib.error
 import urllib.parse
@@ -35,6 +36,7 @@ def _fetch_json_sync(path: str, params: dict | None = None, max_retries: int = 3
     if not key:
         raise RuntimeError("BZZOIRO_KEY 未设置")
 
+    last_exc: Exception | None = None
     for attempt in range(max_retries):
         try:
             req = urllib.request.Request(url)
@@ -43,12 +45,25 @@ def _fetch_json_sync(path: str, params: dict | None = None, max_retries: int = 3
             with urllib.request.urlopen(req, timeout=30) as resp:
                 return _json.loads(resp.read().decode("utf-8"))
         except urllib.error.HTTPError as e:
+            last_exc = e
             if e.code == 429:
-                logger.warning("bzzoiro 429, retry %d", attempt + 1)
-                _time.sleep(1)
+                # 指数退避: 429 通常意味着限速
+                delay = min(2 ** attempt, 16) + random.uniform(0, 1)
+                logger.warning("bzzoiro 429, retry %d in %.1fs", attempt + 1, delay)
+                _time.sleep(delay)
                 continue
-            raise
-    raise RuntimeError("bzzoiro rate limit exceeded")
+            if 500 <= e.code < 600:
+                delay = min(2 ** attempt, 16) + random.uniform(0, 1)
+                logger.warning("bzzoiro %d, retry %d in %.1fs", e.code, attempt + 1, delay)
+                _time.sleep(delay)
+                continue
+            raise  # 4xx 直接抛
+        except (urllib.error.URLError, TimeoutError, ConnectionError) as e:
+            last_exc = e
+            delay = min(2 ** attempt, 16) + random.uniform(0, 1)
+            logger.warning("bzzoiro network error, retry %d in %.1fs: %s", attempt + 1, delay, e)
+            _time.sleep(delay)
+    raise RuntimeError(f"bzzoiro request failed after {max_retries} attempts: {last_exc}")
 
 
 async def fetch_bzzoiro_events(