Add @copilot coding agent as a Squad member type #12

Summary

Add the GitHub Copilot coding agent (@copilot) as a first-class member type in Squad, alongside AI agents (✅) and humans (👤). When enabled, the team Lead can triage issues to @copilot and the coding agent picks them up autonomously — creating branches, writing code, and opening draft PRs.

Motivation

Squad teams already include AI agents and humans. The Copilot coding agent is a natural fit — it can handle well-scoped implementation tasks (bug fixes, tests, docs, refactors) assigned via GitHub issues. Making it a first-class member type means:

• Lead-driven triage: The Lead evaluates issues against a capability profile before routing to @copilot
• Auto-assign workflow: Label an issue squad:copilot and the agent picks it up automatically
• Structured context: copilot-instructions.md gives the agent awareness of the squad's roster, routing, and conventions

Proposed changes

New member type: 🤖 Coding Agent

• 🤖 Coding Agent badge distinguishes from ✅ Active (AI) and 👤 Human
• Three-tier capability profile (🟢 good fit / 🟡 needs review / 🔴 not suitable) in team.md
• @copilot exempt from universe casting (like Scribe)

Enable paths

1. Conversation (recommended): "I want to add copilot to the squad", "hire copilot to the squad", "add team member copilot"
2. Init-time question: Squad asks during init if you want to include the coding agent
3. CLI fallback: npx squad copilot for repos where "copilot" is a project domain word

Auto-assign workflow

• squad:copilot label triggers assignment of copilot-swe-agent[bot]
• Requires a classic PAT (COPILOT_ASSIGN_TOKEN) with repo scope as a repo secret
• Posts routing comment, assigns agent, agent opens draft PR

copilot-instructions.md

• Template providing autonomous coding context: team roster, routing rules, capability self-check, branch naming

Setup requirements

• Copilot coding agent enabled in repo Settings → Copilot
• copilot-setup-steps.yml in .github/
• Classic PAT with repo scope stored as COPILOT_ASSIGN_TOKEN secret (for auto-assign)