CLI: wildgecu agent add <name> bootstrap

[ludusrusso]

Parent PRD

#34

What to build

The wildgecu agent add <name> CLI command. Creates the agent directory under agents/<name>/, runs a bootstrap interview (reusing the existing mechanism from cmd/init.go), and writes SOUL.md and config.yaml. Asks for model preference during setup.

End-to-end: user runs wildgecu agent add researcher, gets an interactive interview, and ends up with a fully configured agent directory.

Acceptance criteria

• wildgecu agent add <name> command registered under wildgecu agent group
• Creates agent directory via Home.Agent(name)
• Runs bootstrap interview (reuses existing bootstrap mechanism)
• Writes SOUL.md from interview result
• Writes config.yaml with chosen model
• Errors if agent already exists (SOUL.md present)
• Validates agent name (alphanumeric + hyphens)

Blocked by

• Blocked by Home.Agent: directory scaffolding for static subagents #41 (Home.Agent directory scaffolding)
• Blocked by Agent config.yaml: parsing and model resolution #42 (agent config.yaml parsing)

User stories addressed

• User story 1 (create named agent)
• User story 7 (bootstrap interview for identity)