- Add squad-post.sh for regular agent messages
- Add squad-event.sh for lifecycle events (spawned/completed/failed/status)
- Add model field to squad messages (types, server, UI, scripts)
- System events render as divider lines in squad chat panel
- Model attribution displays next to agent names in UI
- Full protocol documented in SQUAD-CHAT-PROTOCOL.md
- Updated CONTRIBUTING.md, README.md, and all SOPs
- Added VK_HOST/VK_PORT env vars to .env.example
4-check cross-model review: 10/10 (Code/GPT-5.1, Func/Grok, Perf/Grok, Sec/GPT-5.1)
Agents: R2-D2 (feature), TARS/CASE/Ava/K-2SO (reviews)
