fix: make the Hub backup scripts runnable on the Linux host

Found by running deploy/hub/backup.sh on the production VM:

- With core.autocrlf=true, `git archive` on the Windows release machine
  shipped the .sh files with CRLF and `sh` aborted on line 4
  ("set: Illegal option -"): backup, restore and seed never ran.
  .gitattributes now forces *.sh to LF.
- Docker creates the bind-mounted backups/ directory as root, so the
  host-side retention `rm` would fail once the 15th dump existed.
  Retention now runs inside the postgres container.

tests/test_deploy_scripts.py covers both.

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

deploy/hub/backup.sh

@@ -9,5 +9,7 @@ STAMP="$(date +%Y%m%d_%H%M%S)"
 FILE="gti_fiscal_${STAMP}.dump"
 $COMPOSE exec -T postgres pg_dump -U gti -d gti_fiscal -Fc -f "/backups/${FILE}"
 [ -s "$DIR/$FILE" ] || { echo "backup empty or missing: $DIR/$FILE" >&2; exit 1; }
-ls -1t "$DIR"/gti_fiscal_*.dump | tail -n +15 | xargs -r rm -f
+# Retention runs inside the container: Docker creates the bind-mounted
+# backup directory as root, so a host-side rm would fail from the 15th dump.
+$COMPOSE exec -T postgres sh -c 'ls -1t /backups/gti_fiscal_*.dump | tail -n +15 | xargs -r rm -f'
 echo "backup ok: $DIR/$FILE"