UI: list available login scripts in address book editor #52
Description
When configuring a web session's login_script field in the address book UI, show a read-only dropdown/list of scripts available in login_scripts_dir.
This would make it easier for admins to see what scripts are deployed when configuring entries, without needing to check the filesystem separately.
Scope: Read-only listing only. Script creation/editing stays server-side (filesystem) as an intentional security boundary — see discussion in #40.
Implementation idea: Add an API endpoint (e.g. GET /api/login-scripts) that returns filenames from login_scripts_dir, and use it to populate a dropdown in the address book web entry form.