Add Cursor↔Kombai drop-box board for near-sync messaging

[billbrietstout]

Summary

Migrates Cursor↔Kombai messaging from the single-file .kombai/MESSAGE-BOARD.md channel to a local directory drop-box at .board-cursor-kombai/ so both sides can poll near-synchronously without committing live traffic.

Repo changes

• Add .board-cursor-kombai/ with tracked README.md (protocol), open.example.md (Decision record leads redraw seed), turn.example.md, and outbox/archive .gitkeeps
• Add root BOARD.md pointer
• Gitignore live open.md, turn.md, outbox contents, and archive contents (keep .gitkeeps)
• Point .kombai/README.md at the new channel; mark MESSAGE-BOARD.example.md deprecated
• Keep ignoring .kombai/MESSAGE-BOARD.md

Near-sync protocol (short)

1. turn.md is exactly cursor | kombai | idle
2. Cursor writes outbox-cursor/YYYYMMDD-HHMMSS-<slug>.md, updates open.md, sets turn to kombai
3. Kombai polls, does design-only work, writes outbox-kombai/..., sets turn to cursor
4. Cursor archives done files, sets turn to idle or next task
5. Never edit the other side’s outbox; never commit live state

Bill bootstrap (after merge)

cd /Users/billstout/Documents/Claude/Projects/AISharedResponsibility.com
git pull
cp .board-cursor-kombai/open.example.md .board-cursor-kombai/open.md
cp .board-cursor-kombai/turn.example.md .board-cursor-kombai/turn.md
# edit turn.md to say kombai when ready

Project store Kombai paste instructions: docs/kombai-board-dropbox-instructions.md in the Context store.