Add Admin Guide and Multi-User Guide pages Two new task-oriented guides, linked from the sidebar, the Home page list, the User Guide accounts section, and Settings: - Admin Guide: roles (owner, admin, user), setting up an instance for other people, user management (deactivate vs delete, owner protections, lockouts), the sharing switches, site-wide integrations, the six admin actions and the audit trail, ownership transfer, and routine maintenance. - Multi-User Guide: private-by-default model, global view (what is shared, what never is, read-only), who can edit what (claims stay with the warranty owner; no new claims on voided warranties), per-user tags/settings/notifications, and Paperless-ngx document ownership with several users, ending in a household setup recipe. All behavior claims verified against the 1.0.5 code and the existing Settings and User Guide reference text.