feat(gh-aw): /squad command — Cast mode (fresh team) #1614

/squad Command — Cast Mode (Default)

Part of #1612 (Squad Agentic Workflows epic).
Depends on: #1613 (shared/squad.md bootstrap component)

Overview

The default mode when /squad is invoked with no URL argument. The agent analyzes the target repo, runs Squad's casting intelligence, and opens a PR with a fully-composed team.

Trigger Patterns

• /squad — basic invocation
• /squad give me a team for this React app — natural language with context
• workflow_dispatch — manual trigger from Actions UI

Agent Behavior

1. Analyze repo: languages, file structure, CI configuration, existing patterns, README
2. Run casting intelligence: select appropriate universe, compose team based on repo needs
3. Generate scaffolding:
   • .squad/ directory (team.md, routing.md, casting/, agents/, decisions/)
   • .github/agents/squad.agent.md (coordinator custom agent)
   • meet-the-squad.md (repo root introduction)
4. Open PR via safe-outputs with descriptive title and body

PR Content

The PR includes the full Squad scaffolding ready for merge:

• Agent charters tailored to the repo's technology stack
• Routing rules based on detected patterns
• Casting registry with allocated names and roles
• Coordinator agent that ties everything together

Acceptance Criteria

• /squad triggers Cast mode when no URL is provided
• Agent correctly analyzes repo languages, structure, and patterns
• Casting intelligence produces a team appropriate to the repo
• Full .squad/ scaffolding is generated and valid
• squad.agent.md coordinator is included
• meet-the-squad.md is generated at repo root
• PR is opened with clear title, body, and diff
• workflow_dispatch trigger works from Actions UI
• Natural language variations (e.g., "give me a team for...") are handled