fix(api): 修復 SentryService.check_dedup Redis import

- get_redis_pool → get_redis (正確函數名稱)
- Phase 10.2.1 E2E 測試發現

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/services/sentry_service.py

@@ -211,15 +211,15 @@ class SentryService:
         Returns:
             bool: True = 應處理, False = 已去重跳過
         """
-        from src.core.redis_client import get_redis_pool
+        from src.core.redis_client import get_redis
 
         if not issue_id:
             return True
 
-        redis = await get_redis_pool()
+        redis = get_redis()
         key = f"sentry_dedup:{issue_id}"
 
-        # 檢查是否已存在
+        # 檢查是否已存在 (redis-py async)
         exists = await redis.exists(key)
         if exists:
             logger.info("sentry_dedup_hit", issue_id=issue_id)