Serve never converts databases: with no paskia.kantadb it points at
'paskia init', or at 'paskia migrate' when legacy *.paskiadb candidates
exist. migrate converts a lone candidate, or the one named by --rp-id
when several exist; the rest stay in place. devserver fails fast with
the same hint. gitignore covers paskia.kantadb and *.converted-bak.
- conftest: bootstrap seeds a localhost realm Config; realm_registry
fixture builds the runtime registry; avatar storage redirected to a
per-test tmp dir; credentials/sessions stamped with the test realm.
- test_cli rewritten for the init/serve split, incl. legacy adoption.
- TestServerConfig replaced by TestRealms covering the realm CRUD API,
cross-realm validation, delete guards and effective-auth-host fallback.
- Avatar/OIDC tests updated for per-realm providers and realm-derived
URLs; obsolete PASKIA_DB path tests removed.
- Make use of its new features and cleanup our interfacing and init/shutdown processes and migrations
- Clean up circular deps, simplify app init
- Add specific pytest for CLI main to cover the changes
LeoVasanko