Replace the remaining deploy procedures with CTXD runbook pointers

The repository still carried operating steps from the deleted runbook:
secret creation and permission commands in deploy/.env.example, build,
restart and restore steps in deploy/compose.yaml, a direct
"docker compose up -d" in mealquest-firewall.service, a manual run in
mealquest-media-backup.service and a dev start command in
compose.dev.yaml. Replace each with a pointer to the named section of
CTXD project mealquest, RUNBOOKS.MD, keeping every variable, path,
owner, mode, port and mount description.

Maestro task e81ed994-a510-48e6-9cf6-e76d5d81f56c.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/systemd/mealquest-media-backup.sh

@@ -16,8 +16,8 @@
 # directory are copied as links (-a), never followed.
 #
 # The media directory is created at deploy time (CTXD project mealquest,
-# RUNBOOKS.MD). If it is missing the job fails; it is never treated as
-# "nothing to back up".
+# RUNBOOKS.MD "Media — nightly rsync"). If it is missing the job fails; it
+# is never treated as "nothing to back up".
 #
 # rsync mirrors into .../mealquest-backups/media/ only: the target ends in
 # a slash, so --delete removes files from that directory and nothing