fix(romhacks): pull the orchestrator image instead of declaring a build

Point the service at registry.ginnoir.com/ginnoir/romhacks-orchestrator:latest
(built by the workflow added in 60121a5, verified pullable on valhalla) and
drop the `build:` context that Portainer never honoured.

This unfreezes stack 28, which has been stuck at 847edff since 2026-06-24:
the containers kept running, so nothing alerted, but no commit had deployed
in two months.

README: document that Portainer builds nothing here, and that re-adding a
`build:` would deadlock the stack again.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

stacks/romhacks/README.md

@@ -37,8 +37,9 @@ Ships idle and safe. It will not export or download until armed:
 2. **Channels**: fill `orchestrator/channels.json` with the per-generation channel
    (or forum) IDs. Add any new file hosts you see to `hosts`.
 3. **Register the stack** in Portainer once (new git stacks need a one-time
-   registration — see memory `portainer-new-stack-registration`). Build is on:
-   Portainer builds `homelab/romhacks-orchestrator` from `./orchestrator`.
+   registration — see memory `portainer-new-stack-registration`). Portainer does
+   **not** build anything: the orchestrator image is built by Gitea Actions and
+   pulled from `registry.ginnoir.com/ginnoir/romhacks-orchestrator:latest`.
 4. **JDownloader FolderWatch**: open the noVNC UI at `http://valhalla:8998`
    (set `VNC_PASSWORD` first), Settings → Extensions → **Folder Watch** → enable,
    add watch folder `/watch`. This is what consumes the orchestrator's crawljobs.
@@ -63,8 +64,18 @@ Ships idle and safe. It will not export or download until armed:
 
 `channels.json` and the scripts are **baked into the image** (Portainer's git-stack
 checkout doesn't reliably bind sibling repo files — see the compose header). So a
-change there needs a **push + rebuild**; if a content-only edit doesn't trigger a
-rebuild, use Portainer → the stack → **Re-pull and redeploy**.
+change under `orchestrator/` needs a **push**, which fires
+`.gitea/workflows/build-romhacks-orchestrator.yml`: it builds the image and pushes
+`registry.ginnoir.com/ginnoir/romhacks-orchestrator` as `:latest` + `:sha-<short>`.
+Portainer then pulls `:latest` on its next 5-min poll (`pull_policy: always`).
+
+Compose has **no `build:`** on purpose — Portainer's auto-update runs
+`docker compose pull` and never `build`, so a build-only image name deadlocks the
+stack. Don't add one back.
+
+To rebuild without a source change, run the workflow manually (Gitea → the repo →
+Actions → *Build romhacks orchestrator image* → **Run workflow**), then Portainer →
+the stack → **Re-pull and redeploy**.
 
 ## Paths