Add test_image to deploy deps and fix pip proxy

- Add test_image to deploy needs (container tests must pass)
- Fix python_tests to use internal PyPI proxy consistently

.gitlab-ci.yml

@@ -124,8 +124,8 @@ python_tests:
       - .pip-cache/
     policy: pull-push
   before_script:
-    - pip install -r backend/requirements.txt
-    - pip install pytest pytest-asyncio pytest-cov httpx
+    - pip install --index-url "$PIP_INDEX_URL" -r backend/requirements.txt
+    - pip install --index-url "$PIP_INDEX_URL" pytest pytest-asyncio pytest-cov httpx
   script:
     - cd backend
     # Only run unit tests - integration tests require Docker Compose services
@@ -175,7 +175,7 @@ frontend_tests:
 # Shared deploy configuration
 .deploy_template: &deploy_template
   stage: deploy
-  needs: [build_image, kics, hadolint, python_tests, frontend_tests, secrets, app_deps_scan, cve_scan, cve_sbom_analysis, app_sbom_analysis]
+  needs: [build_image, test_image, kics, hadolint, python_tests, frontend_tests, secrets, app_deps_scan, cve_scan, cve_sbom_analysis, app_sbom_analysis]
   image: deps.global.bsf.tools/registry-1.docker.io/alpine/k8s:1.29.12
 
 .helm_setup: &helm_setup