XceAdminError base plus 8 subclasses (schema-not-found, validation, reserved-name, duplicate-entry, connection-timeout, reply-decode, too-many-redirects, no-primary) giving the future CLI layer one dispatch surface instead of catching unrelated types per module. Requirements: 7.1, 7.2, 7.3, 7.4
Editable-installable xceadmin package with a real click-group entry point (zero subcommands yet) and xcecommon as an independently importable standalone package. Requirements: 5.4
