feat(admin): bake changelog into UI image at CI build time

Replace runtime Gitea API fetch with fs.readFileSync of releases.json,
which CI writes to ui/static/ before the Docker build context is sent.
Eliminates prod→homelab network dependency for the changelog page.

.gitea/workflows/release.yaml

@@ -190,6 +190,14 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Fetch releases from Gitea API
+        run: |
+          curl -sf \
+            -H "Accept: application/json" \
+            "http://gitea.kalekber.cc/api/v1/repos/kamil/libnovel/releases?limit=50&page=1" \
+            -o ui/static/releases.json
+          echo "Fetched $(jq length ui/static/releases.json) releases"
+
       - uses: docker/setup-buildx-action@v3
 
       - name: Log in to Docker Hub