Harvested entities API

GET /api/agents/:id/entities/github/:type (Nitro file server/api/agents/[id]/entities/[service]/[type].get.ts) returns harvested GitHub entities for agent owners where :type is one of repositories, organizations, or teams (mapped to internal entity kinds).

Non-GitHub services currently return errors; the pattern is extensible if additional harvesters land.

Responses include entity lists plus harvest metadata (timestamps/status) so the policy UI can constrain resources to repos the installation actually sees.