chore(deps): bump python in /backend in the docker-all group

Bumps the docker-all group in /backend with 1 update: python.


Updates `python` from 3.11-slim to 3.14-slim

---
updated-dependencies:
- dependency-name: python
  dependency-version: 3.14-slim
  dependency-type: direct:production
  dependency-group: docker-all
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backend/Dockerfile

@@ -1,5 +1,5 @@
 # 使用官方 Python 3.11 slim 镜像
-FROM python:3.11-slim
+FROM python:3.14-slim
 
 # 设置工作目录
 WORKDIR /app