Change default HOST_PORT to 5057 — 5056 is actually taken by arr-summary

arr-summary's own docs say 5055, but it's really deployed on 5056
(confirmed via docker ps on the Unraid box), which collided with
massprice's original default.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H6TgffxTvYhqxykAbVQg2v

.claude/skills/deploy-massprice/SKILL.md

@@ -7,7 +7,9 @@ description: Use when deploying MassPrice Scheduler, restarting the massprice co
 
 **Target:** Unraid server, container path `/mnt/user/appdata/massprice`,
 built from `Dockerfile`/`docker-compose.yml` in this repo. Container name
-`massprice`, port `5056` (overridable via `HOST_PORT`) → container port
+`massprice`, port `5057` (overridable via `HOST_PORT` — `5056` was
+already taken by `arr-summary`, despite its own docs saying `5055`) →
+container port
 `5000`.
 
 **Deploy mechanism: Forgejo push-to-deploy**, the same pattern as