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.

server/README.md

@@ -277,11 +277,17 @@ Pages: `/` (routing hub), `/setup`, `/login`, `/claim`, `/settings`,
 
 Every push to `main` that touches `server/` triggers a Gitea Actions
 workflow (`.gitea/workflows/server-docker-build.yml`) that builds this
-image and pushes it to this repo's Gitea Container Registry at
-`git.thumeit.com/tfaour/espresso-frame-server`. `docker-compose.yml`
-(copied from `docker-compose.yml.example`, see Setup above) already
-points at that image, so a deploy host doesn't need this repo's build
-context at all -- just the compose file:
+image and pushes it to a LAN-local Gitea Container Registry at
+`10.0.0.246:3000/tfaour/espresso-frame-server` -- not the `git.thumeit.com`
+source repo itself; Cloudflare (fronting that host) started rejecting
+pushes with 413 Payload Too Large once whiteboard mode's Node/native-
+binding layers made the image significantly bigger, and this address
+has nothing in front of it to hit that limit. A deploy host reaching
+this registry needs Docker's `insecure-registries` configured for it if
+it's plain HTTP (see `daemon.json`) -- not something this repo controls.
+`docker-compose.yml` (copied from `docker-compose.yml.example`, see
+Setup above) already points at that image, so a deploy host doesn't
+need this repo's build context at all -- just the compose file:
 
 ```
 docker compose pull