Task 1 of the Instance Picker plan (docs/plans/2026-09-08-instance-picker.md).
Pure, DI-free builder that nests a site's areas by ParentAreaId and hangs each
area's instances beneath it, mirroring Topology's ordering (child areas first,
then that level's instances; OrdinalIgnoreCase sorts) with unparented instances
at the root after the root areas. Orphaned areas become roots, a case-insensitive
filter keeps matching instances plus their ancestors and drops empty branches,
and a ParentAreaId cycle can never recurse forever.
Claude-Session: https://claude.ai/code/session_01NcMG6xXdsJbmD2wYAgkK29
Joseph Doherty
f12ba2f9eb