Push server image to local registry instead of git.thumeit.com

Cloudflare (fronting git.thumeit.com) started rejecting image pushes
with 413 Payload Too Large once whiteboard mode's Node runtime + native
resvg bindings made the image significantly bigger than before. Switched
the build/push target to a LAN-local registry (10.0.0.246:3000) that has
nothing in front of it to hit that limit, and updated
docker-compose.yml.example to match.

.gitea/workflows/server-docker-build.yml

@@ -17,10 +17,15 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
-      - name: Log in to Gitea Container Registry
+      - name: Log in to local Gitea Container Registry
         uses: docker/login-action@v3
         with:
-          registry: git.thumeit.com
+          # Pushed here instead of git.thumeit.com (still the source repo,
+          # just not the image registry anymore) -- since whiteboard mode
+          # added Node + native resvg bindings, the image grew past
+          # Cloudflare's payload-size limit in front of that host and
+          # every push 413'd. This LAN address has nothing in front of it.
+          registry: 10.0.0.246:3000
           username: tfaour
           password: ${{ secrets.REGISTRY_TOKEN }}
 
@@ -30,5 +35,5 @@ jobs:
           context: ./server
           push: true
           tags: |
-            git.thumeit.com/tfaour/espresso-frame-server:latest
-            git.thumeit.com/tfaour/espresso-frame-server:${{ gitea.sha }}
+            10.0.0.246:3000/tfaour/espresso-frame-server:latest
+            10.0.0.246:3000/tfaour/espresso-frame-server:${{ gitea.sha }}