~anthropic/claude-sonnet-latest → A (6:4)

Side A consolidates duplicated room-route parsing logic into shared, validated helpers (room_route_segment/room_id_from_route_segment) used consistently across many endpoints and tests, and adds a substantive, well-tested URL-identity normalization layer (query sorting, YouTube canonicalization) that fixes real duplicate-identity bugs in the ontology system. Side B is a valid, narrower bugfix (Reddit child import wiring and unranked-label rendering) but touches far less surface area and adds less lasting infrastructure than A's DRY refactor plus new normalization module and its 20+ regression tests.