feat: add ci pipeline

.gitlab-ci.yml

+image: node:alpine
+
+workflow:
+  rules:
+    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
+    - if: $CI_PIPELINE_SOURCE == "web"
+    - if: $CI_COMMIT_BRANCH == "main"
+
+
+build:
+  stage: build
+  variables:
+    GIT_STRATEGY: fetch
+  script:
+  # Replacing the whole Astro config is a temporary workaround b/c Astro
+  # currently doesn't support env variables inside of the config file.
+  # See: https://github.com/withastro/astro/issues/3897
+    - echo "$ASTRO_CONFIG" > astro.config.mjs
+    - cat astro.config.mjs
+    - npm ci
+    - npm run build
+  artifacts:
+    name: "$CI_COMMIT_REF_SLUG"
+    expire_in: 1 day
+    paths:
+      - dist
+  environment:
+    name: $CI_COMMIT_REF_SLUG
+    url: $TARGET_HOST/$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG
+
+deploy:
+  stage: deploy
+  variables:
+    GIT_STRATEGY: none
+  before_script:
+    - apk update
+    - apk add --no-cache lftp openssh
+    - mkdir -p ~/.ssh
+    - echo "$SSH_KNOWN_HOSTS" >> ~/.ssh/known_hosts
+    - echo "Deploying for branch $CI_COMMIT_REF_SLUG – will be available at 🌎 $TARGET_HOST/$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG"
+  script:
+    - lftp -e "set ftp:list-options -a; set net:timeout 5; set net:max-retries 3; set net:reconnect-interval-base 5; open sftp://$SFTP_HOST; user $SFTP_USER $SFTP_PASSWORD; mirror --reverse --delete ./dist/ $SFTP_FOLDER/$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG/; bye"
+  environment:
+    name: $CI_COMMIT_REF_SLUG
+    url: $TARGET_HOST/$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG
+    on_stop: delete
+
+delete:
+  stage: deploy
+  variables:
+    GIT_STRATEGY: none
+  before_script:
+    - apk update
+    - apk add --no-cache lftp openssh
+    - mkdir -p ~/.ssh
+    - echo "$SSH_KNOWN_HOSTS" >> ~/.ssh/known_hosts
+  script:
+    - lftp -e "set ftp:list-options -a; set net:timeout 5; set net:max-retries 3; set net:reconnect-interval-base 5; open sftp://$SFTP_HOST; user $SFTP_USER $SFTP_PASSWORD; rm -r $SFTP_FOLDER/$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG/; bye"
+  when: manual
+  environment:
+    name: $CI_COMMIT_REF_SLUG
+    action: stop