Add a dynamic config option to set the default landing page for
unauthenticated visitors from Site Administration > Settings. Options:
- Home (default explore page)
- Explore (repository explore)
- Organizations (org explore)
- Login (redirect to login)
- Custom path (any internal URL like /MokoConsulting)
The setting takes effect immediately without restart, using the same
dynamic config system as maintenance mode and web banner. Falls back
to the static LANDING_PAGE setting from app.ini if not configured.
Closes#240
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>