Almost Heaven final auth/fallback audit pass

Changes made:
- Local fallback login kept active through admin/users.txt
- External auth remains the primary source when present
- Local fallback users are now merged in automatically, so testing works without renaming external auth folders
- User save routine now falls back to admin/users.txt when external auth storage is unavailable
- Auth config path remains: C:/inetpub/Authentication/almostheaven/auth_config.php
- API config path remains: C:/inetpub/Authentication/api/almostheaven.php

Audit recheck completed:
- Local fallback login tested successfully with admin/users.txt
- Dashboard loaded after login
- Public pages rechecked: home, about, chat, contact, events, friends, news, requests, schedule, top50
- Admin pages rechecked: comments, poll, file-finder
- PHP syntax check passed for updated auth files

Tested fallback credentials from admin/users.txt at packaging time:
- admin / smurfette
