The agent:// path segment was always treated as a jq JSON-extraction key
against <parent>.md, so agent://Parent/Child loaded Parent.md and applied
.Child instead of resolving the nested child capsule Parent.Child.md. A
precise-planner reading its own scout child therefore got Not found.
The slash is now a hierarchy separator first: agent://Parent/Child resolves
Parent.Child.md (subagent children are allocated as dot-qualified ids). It
falls back to JSON extraction only when no nested output matches the path;
the ?q= query form is always extraction.
Fixes#5238
roboomp
8c6b2fb450