feat(gh-aw): /squad adopt {url} — Adopt mode (fork squad) #1616

/squad adopt {url} — Adopt Mode

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

Overview

Template/fork mode. Pulls a squad from a remote source and copies it fully into the target repo via PR. After merge, the squad is local — the user owns it completely and can customize freely. No ongoing connection to the source.

Trigger Pattern

• /squad adopt bradygaster/xtenders
• /squad adopt acme-corp/starter-squad

Agent Behavior

1. Parse the source URL from the command
2. Fetch the full squad definition from the source repo
3. Copy complete .squad/ scaffolding + squad.agent.md into target repo
4. Adapt any repo-specific references (update routing for target repo's structure)
5. Generate meet-the-squad.md noting the squad was adopted from source
6. Open PR with the full squad committed locally

Use Cases

• Team templates: Organization maintains starter squads for different project types
• Starter squads: Quick-start with an opinionated team, then customize
• Opinionated presets: Community-shared squad configurations (e.g., "the OSS maintainer squad")
• Fork and customize: Start from a known-good team, then evolve independently

Difference from Connect Mode

Acceptance Criteria

• /squad adopt org/repo triggers Adopt mode
• Full .squad/ scaffolding is copied from source to target
• squad.agent.md coordinator is included in the PR
• meet-the-squad.md notes the adoption source
• After merge, squad is fully local with no remote dependency
• Squad files can be freely edited after adoption
• Cross-org access works with GitHub App token
• Invalid/inaccessible source URLs produce clear error messages
• Basic adaptation of repo-specific references is performed