Implement ucas template subcommands for managing template storage:
- template set <schema-hash> <file> | --inline <text>: Store template text in CAS
- template get <schema-hash>: Retrieve template as raw text
- template list: List all templates with preview
- template delete <schema-hash>: Delete template variable binding
Templates are stored as plain text under @string schema and bound to
variables using the naming pattern @ucas/template/text/<schema-hash>.
Fixes#38
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
xiaoju