Add branch preview deployment and local testing

- Add preview environment for feature branch testing
- Create local deployment test script
- Enable testing without requiring main branch
- Preview URL: project-branch.gitlab.io

.gitlab-ci.yml

@@ -32,6 +32,23 @@ deploy:
     paths:
       - public
 
+# Branch preview deployment (for testing)
+preview:
+  stage: deploy
+  script:
+    - echo "Deploying branch preview..."
+    - echo "Preview available at: ${CI_ENVIRONMENT_URL}"
+  needs:
+    - deploy
+  artifacts:
+    paths:
+      - public
+  environment:
+    name: preview/$CI_COMMIT_REF_SLUG
+    url: https://${CI_PROJECT_PATH_SLUG}-${CI_COMMIT_REF_SLUG}.gitlab.io
+  rules:
+    - if: "$CI_COMMIT_BRANCH != $CI_DEFAULT_BRANCH"
+
 # GitLab Pages deployment (only on main branch)
 pages:
   stage: deploy