Add Build Remote Agent phone pairing (gbr/1)

[LinespottingPrivate]

What

Optional Build Remote Agent pairing device so a phone can spectate this desktop agent.

Protocol stays gbr/1 (not a fourth pair protocol):

1. Install gbr-agent v0.6.0+ from https://grokbuildremote.com/
2. gbr-agent pair — browser QR and printed 8-char code
3. Phone scans or types the code
4. gbr-agent run (leave running)
5. Attach only http://127.0.0.1:8788 or gbr-mcp stdio

Phone is spectator + veto. Orchestration stays on this agent.

Independent product by Linespotting AB. Not affiliated with xAI or SpaceX.

Agent source (MIT): https://github.com/LinespottingOrg/GrokBuildRemote-Agents

Files

Docs / MCP snippet only. No product-runtime change. No mailbox keys.

curl -fsSL https://grokbuildremote.com/install.sh | bash
gbr-agent version    # need v0.6.0+
gbr-agent pair && gbr-agent run
curl -sS http://127.0.0.1:8788/health