feat(memory): add memory CLI command group and project memory ADRs
- Add docs/adr/ADR-001-workplan-convention.md (formalises existing convention)
- Add docs/adr/ADR-002-project-memory-convention.md (file location, structure,
session protocols, opt-out, CLI interface)
- Implement `kaizen-agentic memory` command group: show, init, brief, clear
- Memory stored at .kaizen/agents/<name>/memory.md in project root
- `init` scaffolds the standard memory template with YAML frontmatter
- `brief` lists all agent memories + note that coach synthesis is pending T13
- `clear` deletes with confirmation prompt
WP-0002 T07 and T08 done.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>