fix: 修复环路检测失败 + 多项UX增强

修复:
- 环路检测正则 \s+(Onu\S+)\s+ → \s+(Onu\S+) (splitlines移除换行后尾随\s无法匹配)
- 权限中间件 Header(...) → Header(None) 避免缺失Auth头返回422而非401
- 环路检测请求超时30s→120s (SSH连接30+台OLT实测需58秒)

重构 (ssh_service.py):
- 提取 _send_and_wait 为私有方法,消除3处重复内部函数
- 添加 __enter__/__exit__ 上下文管理器支持
- 加固 execute_command prompt检测 (按行匹配<DEVICE_NAME>)
- 移除未使用的settings import
- olt.py/devices.py 调用方改用 with 语法

新功能:
- 侧边栏退出登录上方显示当前用户名和角色
- 版本号从VERSION文件自动读取 (后端/health返回,前端动态显示)
- 基于广西南宁经纬度计算日落时间,自动切换深色/浅色主题
- /api/olt/loopback-detection 响应增加raw字段便于排查

基础设施:
- CLAUDE.md 加入 .gitignore
- 新增 .claude/rules/07-remote-operations.md (远程部署操作)
- 新增 .claude/rules/08-frp-notes.md (frp隧道注意事项)
- 新增 VERSION 文件 (版本号 0.10.0)
- 新增环路检测解析测试用例 (5个)

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

backend/app/middleware/permission_middleware.py

@@ -1,8 +1,11 @@
 """权限检查中间件（数据库驱动 + Redis 缓存）"""
 import json
+import logging
 from fastapi import HTTPException, Depends, Header
 from sqlalchemy.orm import Session
 from sqlalchemy import text
+
+logger = logging.getLogger(__name__)
 import redis
 
 from app.core.database import get_db
@@ -52,14 +55,19 @@ def invalidate_role_cache(role: str) -> None:
 def require_permission(permission: str):
     """FastAPI Depends 工厂，检查 Bearer token 中的角色是否拥有指定权限"""
     def dependency(
-        authorization: str = Header(..., alias="Authorization"),
+        authorization: str = Header(None, alias="Authorization"),
         db: Session = Depends(get_db),
     ) -> dict:
+        if not authorization:
+            logger.warning("auth rejected: 缺少 Authorization 头 (permission=%s)", permission)
+            raise HTTPException(status_code=401, detail="未授权")
         if not authorization.startswith("Bearer "):
+            logger.warning("auth rejected: Authorization 格式错误 (permission=%s): %.50s", permission, authorization)
             raise HTTPException(status_code=401, detail="未授权")
         token = authorization[7:]
         payload = verify_token(token)
         if not payload:
+            logger.warning("auth rejected: token 验证失败 (permission=%s): token前20字符=%.20s...", permission, token[:20])
             raise HTTPException(status_code=401, detail="令牌无效或已过期")
 
         role = payload.get('role', 'user')
@@ -83,11 +91,11 @@ def require_permission(permission: str):
 
 
 def get_current_user(
-    authorization: str = Header(..., alias="Authorization"),
+    authorization: str = Header(None, alias="Authorization"),
     db: Session = Depends(get_db),
 ) -> dict:
     """仅验证登录状态，不检查具体权限"""
-    if not authorization.startswith("Bearer "):
+    if not authorization or not authorization.startswith("Bearer "):
         raise HTTPException(status_code=401, detail="未授权")
     token = authorization[7:]
     payload = verify_token(token)