Return newly added fields from routing.agents config:
- sandbox: agent-specific sandbox configuration
- tools: agent-specific tool restrictions
This makes per-agent sandbox and tool settings accessible
to other parts of the codebase.
- Onboarding now writes auth profiles under ~/.clawdbot/agents/main/agent so the gateway sees credentials on first start.
- Hardened onboarding test to ignore legacy env vars.
Thanks @minghinmatthewlam!