The projects this credential may act on
Discovery for multi-project connections (GRE-499). An MCP OAuth bearer (mcp_at_…) may be attached to SEVERAL projects, each with its OWN scopes; this returns them all, with is_default marking the one used when a call names no project. Pass a returned id in the X-Paige-Project header to target a project. A pk_ API key is a single project’s context and returns that one project as a one-element list (same shape), so a client never needs to branch on credential type.
Deliberately NOT project-selected: it stays usable when the default project is paused (which would otherwise 403 project_inactive), so a client can always discover a healthy sibling. The X-Paige-Project header is ignored here.
Required scope: any valid key.
