fix: 路由顺序导致 422 + 彻底消除 Header(...) 隐患

1. devices.py: /tags 和 /export/csv 移到 /{device_id}(int) 之前，
   避免 FastAPI 将 'tags'/'export' 当作 device_id 解析失败返回 422
2. audit.py: /logs/export/csv 移到 /logs/{log_id}(int) 之前，同上
3. auth.py: Header(...) → Header(None)，统一为手动 401 返回，
   消除全局最后一个 Header(...) 导致的 422 隐患

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

backend/app/api/v1/devices.py

@@ -338,6 +338,55 @@ def export_replacements(
     )
 
 
+@router.get("/tags")
+def get_all_tags(db: Session = Depends(get_db)):
+    """获取所有不重复的设备标签"""
+    from sqlalchemy import func as _func
+    rows = db.query(ONUDevice.tags).filter(
+        ONUDevice.tags.isnot(None), ONUDevice.tags != ''
+    ).all()
+    tags = set()
+    for (tag_str,) in rows:
+        for t in tag_str.split(','):
+            t = t.strip()
+            if t:
+                tags.add(t)
+    return sorted(tags)
+
+
+@router.get("/export/csv")
+def export_devices_csv(
+    region: Optional[str] = Query(None),
+    school_name: Optional[str] = Query(None),
+    db: Session = Depends(get_db),
+    _: dict = Depends(require_permission('device.view')),
+):
+    """导出设备列表为 CSV"""
+    from sqlalchemy import func as _func
+
+    query = db.query(ONUDevice)
+    if region:
+        query = query.filter(ONUDevice.region == region)
+    if school_name:
+        query = query.filter(ONUDevice.school_name == school_name)
+    devices = query.order_by(ONUDevice.region, ONUDevice.school_name).all()
+
+    output = io.StringIO()
+    writer = csv.writer(output)
+    writer.writerow(["MAC地址", "区域", "学校", "楼宇", "场所类型", "房间号", "端口", "型号", "LOID", "距离(m)", "备注"])
+    for d in devices:
+        writer.writerow([d.mac_address, d.region or "", d.school_name or "", d.building or "",
+                         d.place_type or "", d.room_number or "", d.port_id or "", d.model or "",
+                         d.loid or "", d.distance_m or "", d.notes or ""])
+
+    output.seek(0)
+    return StreamingResponse(
+        iter([output.getvalue()]),
+        media_type="text/csv",
+        headers={"Content-Disposition": "attachment; filename=onu_devices.csv"}
+    )
+
+
 @router.get("/{device_id}", response_model=ONUDeviceResponse)
 def get_device(
     device_id: int,
@@ -701,52 +750,3 @@ def get_optical_power_history(
          "recorded_at": r.recorded_at.isoformat() if r.recorded_at else None}
         for r in rows
     ]
-
-
-@router.get("/tags")
-def get_all_tags(db: Session = Depends(get_db)):
-    """获取所有不重复的设备标签"""
-    from sqlalchemy import func as _func
-    rows = db.query(ONUDevice.tags).filter(
-        ONUDevice.tags.isnot(None), ONUDevice.tags != ''
-    ).all()
-    tags = set()
-    for (tag_str,) in rows:
-        for t in tag_str.split(','):
-            t = t.strip()
-            if t:
-                tags.add(t)
-    return sorted(tags)
-
-
-@router.get("/export/csv")
-def export_devices_csv(
-    region: Optional[str] = Query(None),
-    school_name: Optional[str] = Query(None),
-    db: Session = Depends(get_db),
-    _: dict = Depends(require_permission('device.view')),
-):
-    """导出设备列表为 CSV"""
-    from sqlalchemy import func as _func
-
-    query = db.query(ONUDevice)
-    if region:
-        query = query.filter(ONUDevice.region == region)
-    if school_name:
-        query = query.filter(ONUDevice.school_name == school_name)
-    devices = query.order_by(ONUDevice.region, ONUDevice.school_name).all()
-
-    output = io.StringIO()
-    writer = csv.writer(output)
-    writer.writerow(["MAC地址", "区域", "学校", "楼宇", "场所类型", "房间号", "端口", "型号", "LOID", "距离(m)", "备注"])
-    for d in devices:
-        writer.writerow([d.mac_address, d.region or "", d.school_name or "", d.building or "",
-                         d.place_type or "", d.room_number or "", d.port_id or "", d.model or "",
-                         d.loid or "", d.distance_m or "", d.notes or ""])
-
-    output.seek(0)
-    return StreamingResponse(
-        iter([output.getvalue()]),
-        media_type="text/csv",
-        headers={"Content-Disposition": "attachment; filename=onu_devices.csv"}
-    )