Fix SSE route dependency and align architecture docs

backend/app/config/logging.py

@@ -1,16 +1,18 @@
-"""日志配置"""
+"""Configure backend settings for logging."""
 
 from loguru import logger
 import sys
+# Keep configuration setup explicit so runtime behavior is easy to reason about.
+
 
 
 def setup_logging(level: str = "INFO"):
-    """设置日志配置"""
+    """Handle setup logging."""
 
-    # 移除默认handler
+    # Keep configuration setup explicit so runtime behavior is easy to reason about.
     logger.remove()
 
-    # 添加控制台输出
+    # Keep configuration setup explicit so runtime behavior is easy to reason about.
     logger.add(
         sys.stdout,
         level=level,
@@ -18,7 +20,7 @@ def setup_logging(level: str = "INFO"):
         colorize=True
     )
 
-    # 添加文件输出
+    # Keep configuration setup explicit so runtime behavior is easy to reason about.
     logger.add(
         "logs/app_{time:YYYY-MM-DD}.log",
         level=level,