chore(deps): bump python in /docker/backend-slim

Bumps python from 3.10-slim to 3.14-slim.

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

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

Author: dependabot[bot]

docker/backend-slim/Dockerfile

@@ -4,7 +4,7 @@
 # Reduces image from ~1.5GB to ~200MB
 # Memory: 4G instead of 24G
 # ============================================
-FROM python:3.10-slim
+FROM python:3.14-slim
 
 WORKDIR /app