Update the README to describe pobsync as a Django-first, SQL-backed
service with the control panel as the primary operational interface.
Move CLI examples out of the normal workflow and document them as
maintainer tooling for debugging, services, and migration tasks.
Teach the systemd installer to install required Debian/Ubuntu
packages by default, with an opt-out for users who manage system
dependencies themselves.
Add explicit MariaDB install-extra handling so native installs can
pull in both the Python extra and required client build packages.
Slim down the README to production setup and operations, and move
development, Docker, migration helper, and architecture notes into
docs/development.md.
