chore(infra): remove night-scheduler service entirely [guardrail-change]

Deletes the night-scheduler (nightly auto-shutdown of services). It stopped
services at 22:00 and killed long-running jobs (e.g. bulk embedding) — net
hindrance. Removed: running container, compose service + hetzner override,
source dir, CI lint entry, rule doc.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docker-compose.hetzner.yml

@@ -162,8 +162,6 @@ services:
     profiles: ["disabled"]
   gitea-runner:
     profiles: ["disabled"]
-  night-scheduler:
-    profiles: ["disabled"]
   admin-core:
     profiles: ["disabled"]
   pitch-deck: