ci: move dev Docker Hub publishing back to GitHub Actions

Publish dev images to both GHCR and Docker Hub from the dev workflow
and drop the GitLab CI pipeline, so all images are built by GitHub
Actions only.

.github/workflows/docker-dev.yml

@@ -1,7 +1,7 @@
 name: Dev images
 
 # On every push to the dev branch, build all three images and push them to
-# GHCR tagged `dev`. Docker Hub dev images are published by GitLab CI.
+# GHCR and Docker Hub tagged `dev`.
 
 on:
   push:
@@ -22,5 +22,4 @@ jobs:
     with:
       push: true
       tag_mode: dev
-      publish_dockerhub: false
     secrets: inherit

.gitlab-ci.yml

@@ -1,72 +0,0 @@
-stages:
-  - docker
-
-workflow:
-  rules:
-    - if: '$CI_COMMIT_BRANCH == "dev"'
-    - when: never
-
-variables:
-  DOCKER_BUILDKIT: "1"
-  DOCKER_DRIVER: overlay2
-  DOCKER_HOST: tcp://docker:2375
-  DOCKER_TLS_CERTDIR: ""
-  GIT_DEPTH: "0"
-
-docker-dev:
-  stage: docker
-  image: docker:27.5.1
-  services:
-    - name: docker:27.5.1-dind
-      alias: docker
-  interruptible: true
-  parallel:
-    matrix:
-      - TARGET: backend
-        IMAGE: remnawave-minishop-backend
-      - TARGET: worker
-        IMAGE: remnawave-minishop-worker
-      - TARGET: frontend
-        IMAGE: remnawave-minishop-frontend
-  before_script:
-    - apk add --no-cache git
-    - test -n "$DOCKERHUB_USERNAME"
-    - test -n "$DOCKERHUB_TOKEN"
-    - echo "$DOCKERHUB_TOKEN" | docker login --username "$DOCKERHUB_USERNAME" --password-stdin
-    - docker buildx create --name gitlab-builder --driver docker-container --use
-    - docker buildx inspect --bootstrap
-  script:
-    - git fetch origin dev --tags
-    - |
-      if [ "$(git rev-parse HEAD)" != "$(git rev-parse origin/dev)" ]; then
-        echo "A newer dev commit exists; skipping Docker Hub build for $IMAGE."
-        exit 0
-      fi
-    - |
-      provenance="${REMNAWAVE_MINISHOP_BUILD_PROVENANCE:-}"
-      if [ -z "$provenance" ]; then
-        dockerhub_owner="$(printf '%s' "${DOCKERHUB_USERNAME:-}" | tr '[:upper:]' '[:lower:]')"
-        if [ "${CI_PROJECT_PATH:-}" = "3252a8/remnawave-minishop" ] || [ "$dockerhub_owner" = "3252a8" ]; then
-          provenance="official"
-        else
-          provenance="custom"
-        fi
-      fi
-      docker buildx build \
-        --load \
-        --platform linux/amd64 \
-        --file deploy/docker/Dockerfile \
-        --target "$TARGET" \
-        --build-arg "CI_COMMIT_REF_NAME=$CI_COMMIT_REF_NAME" \
-        --build-arg "REMNAWAVE_MINISHOP_BUILD_PROVENANCE=$provenance" \
-        --build-arg "BUILDKIT_INLINE_CACHE=1" \
-        --cache-from "type=registry,ref=$DOCKERHUB_USERNAME/$IMAGE:dev" \
-        --tag "$DOCKERHUB_USERNAME/$IMAGE:dev" \
-        .
-    - git fetch origin dev --tags
-    - |
-      if [ "$(git rev-parse HEAD)" != "$(git rev-parse origin/dev)" ]; then
-        echo "A newer dev commit exists; skipping Docker Hub push for $IMAGE."
-        exit 0
-      fi
-    - docker push "$DOCKERHUB_USERNAME/$IMAGE:dev"