PROJ-035 Live Status v4 - implementation plan created by planner subagent.
Discovery findings documented in discoveries/README.md covering:
- JSONL transcript format (confirmed v3 schema)
- Session keying patterns (subagent spawnedBy linking)
- Hook events available (gateway:startup confirmed)
- Mattermost API (no edit time limit)
- Current v1 failure modes
Audit: 32/32 PASS, Simulation: READY
