Addresses Claude's review:
- Acceptance criteria (done-when) for all 8 open items
- PROTOCOL.md must be generated from wire.go, not freehand
- Resolved CalDAV: Radicale, new cmd/mavcaldav module
- Reordered to core→capabilities→harden priority
- Hard guard: multi-user schema is do-not-touch this phase
- Dropped Nextcloud mention
kami