Add `mosaic fleet provision --profile <id> [--full] [--write] [--force]`:
materialize a concrete, parser-valid roster.yaml from a declared system-type
profile. DRY-RUN by default (prints roster + topology, writes nothing); --write
persists under <mosaicHome>/fleet/roster.yaml and refuses to clobber without
--force. Reuses loadProfile/validateProfile (fleet-profiles) and resolvePersona
(fleet-personas, override-aware); generation policy is local + documented.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>