library: seed label templates/layouts, default item type, fix Apache setup

- Seed Avery 5160/5167 and Demco spine templates plus Spine, Spine+barcode
  and Barcode-only layouts (Dewey call number split across lines)
- Default 942$c (item type) to BOOK so a Z39.50 import saves without edits
- Enable Plack includes in addition to the plain ones (static files/rewrites)
- Swap Apache from mpm_itk to prefork after koha-create (itk can't switch
  users in a container and returned HTTP 500 on every page)
- Drop unneeded SETUID/SETGID caps

Verified live: staff login, Z39.50 search/import against a local server,
save + auto barcode, label PDF with Dewey spine + barcode.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013wi3ZSot4XbUViwRFgLpRf

library/docker-compose.yml

@@ -37,10 +37,6 @@ services:
       KOHA_ADMIN_USER: ${ADMIN_USER:-admin}
       KOHA_ADMIN_PASS: ${ADMIN_PASSWORD}
       KOHA_LIBRARY_NAME: ${LIBRARY_NAME:-My Library}
-    # Koha's Apache uses mpm_itk, which switches users per request.
-    cap_add:
-      - SETUID
-      - SETGID
     ports:
       - "${OPAC_PORT:-8080}:80"
       - "${STAFF_PORT:-8081}:8081"