🐛💚 ci: Fix Antora build that has never passed on Forgejo

Every CI run since migration failed at the `upload-artifact@v4` step,
which rejects non-GitHub forges with `GHESNotSupportedError`. The Antora
build itself always succeeded. Remove `upload-artifact` (it served no
deployment purpose) and the stale `.gitlab-ci.yml` alongside it.

Add `--log-failure-level fatal` to the `build-pages` job so cross-repo
`xref` warnings (`marketing::`, `council::`, etc.) are visible in the
Actions log but don't block the build. The `build-preview` job already
had this flag.

Assisted-by: Claude Opus 4.6 (1M context)
Signed-off-by: Justin W. Flory <jflory7@fedoraproject.org>
Signed-off-by: Justin Wheeler <jwheel@redhat.com>

.forgejo/workflows/ci.yaml

@@ -1,10 +1,8 @@
 ---
 name: Antora docs CI
 on:
-  # Run on PRs
   pull_request:
     types: [opened, synchronize, reopened]
-  # Run on pushes to main
   push:
     branches:
       - main
@@ -18,39 +16,27 @@ jobs:
     container:
       image: antora/antora:latest
     steps:
-      - name: Install git (needed for Antora)
+      - name: Install git
         run: apk add --no-cache git
 
       - name: Checkout repo
         uses: actions/checkout@v6
 
-      - name: Build Antora site (preview)
+      - name: Build Antora site
         run: antora --log-failure-level fatal site.yml
 
-      - name: Upload site artifact
-        uses: actions/upload-artifact@v4
-        with:
-          name: docs-preview
-          path: public/
-
   build-pages:
-    name: Build pages (main, fedora namespace)
+    name: Build pages (main, mindshare namespace)
     runs-on: podman
     if: forgejo.event_name == 'push' && forgejo.ref == 'refs/heads/main' && forgejo.repository_owner == 'mindshare'
     container:
       image: antora/antora:latest
     steps:
-      - name: Install git (needed for Antora)
+      - name: Install git
         run: apk add --no-cache git
 
       - name: Checkout
         uses: actions/checkout@v6
 
       - name: Build Antora site
-        run: antora site.yml
-
-      - name: Upload site artifact
-        uses: actions/upload-artifact@v4
-        with:
-          name: docs-main
-          path: public/
+        run: antora --log-failure-level fatal site.yml

.gitlab-ci.yml

@@ -1,29 +0,0 @@
-build:
-  stage: build
-  image:
-    name: antora/antora:latest
-  script:
-  - antora --log-failure-level fatal site.yml
-  artifacts:
-    paths:
-    - public/
-    expire_in: 1 week
-    expose_as: 'docs preview'
-  rules:
-  - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
-  environment:
-    name: preview MR_${CI_MERGE_REQUEST_IID}
-    url: https://${CI_SERVER_HOST}/${CI_PROJECT_PATH}/-/jobs/${CI_JOB_ID}/artifacts/file/public/index.html
-    auto_stop_in: 1 week
-pages:
-  stage: build
-  image:
-    name: antora/antora:latest
-  script:
-  - antora site.yml
-  artifacts:
-    paths:
-    - public
-  rules:
-  - if: $CI_COMMIT_BRANCH == "main" && $CI_PROJECT_ROOT_NAMESPACE == "fedora"
-