Why: W3 remainder is implemented on RDM draft PR #451 and needs the user's stage 6 review before merging into the initiative. Evidence: RDM f3fa0c0 target tests and domain/rdmapp packages pass locally (SELF); fresh-session review PASS-with-fixes with no blocking findings. Impact: task cards and review docs only; placement checks recorded as a W4 write-entry prerequisite. Refs: feature/rdm-two-trees-followup-w3-rest, RDM PR #451 Co-authored-by: Cursor <cursoragent@cursor.com>