Phase 1: workflow subcommand group (add/list/show/rm/history/rollback)
Phase 2: thread subcommand group (run/list/show/rm/fork/ps/kill/live/pause/resume)
Phase 3: cas gc + top-level aliases + deprecation warnings for old flat commands
- Follow existing CAS_SUBCOMMAND_TABLE pattern for workflow and thread groups
- Top-level 'run' and 'live' stay as shortcuts (no deprecation)
- Old flat commands print deprecation warning then delegate
- Update usage string to show grouped format
- Update tests to use new grouped syntax
- MerkleNode type: { type, payload, children } serialized as YAML
- RoleOutput.content → contentHash (CAS hash of Merkle content node)
- Engine stores content in global CAS before writing to .data.jsonl
- create-workflow puts content as Merkle node, merges contentHash into refs
- fork/parse adapted for contentHash format
- buildAgentPrompt now async, reads content from CAS
- Bundle validator allows @uncaged/workflow import
- 150 tests passing
BREAKING: .data.jsonl no longer contains inline content
Fixes#41