The has_provider_auth check and egress-placeholder injection were
duplicated in both backends. Move them into agent_provision_plan so
the provisioner owns that decision entirely:
- Replace has_provider_auth: bool param with manifest_egress_routes,
compute has_provider_auth internally from the route roles.
- Inject CLAUDE_CODE_OAUTH_TOKEN=egress-placeholder inside the plan
when has_provider_auth, alongside the existing nonessential-traffic
vars. Backends no longer touch the placeholder env.
- Remove placeholder_env from AgentProviderRuntime; expose
placeholder_env_for() for print_util's hide-from-summary logic.
Assisted-by: Claude Code