docs(phase29ao): add coreplan done criteria ssot

docs/development/current/main/30-Backlog.md

@@ -5,14 +5,8 @@ Scope: 「次にやる候補」を短く列挙するメモ。入口は `docs/dev
 
 ## Active
 
-- CorePlan migration: `docs/development/current/main/phases/phase-29ao/README.md`（Next: TBD, P54 done）
-
-## Near-Term Candidates
-
+- Phase 29ap (planned): legacy削減の段階計画（extractor/router）+ composer SSOT
 - JoinIR regression gate SSOT: `docs/development/current/main/phases/phase-29ae/README.md`
 - CorePlan hardening (docs-first): `docs/development/current/main/phases/phase-29al/README.md`
-- CorePlan lowerer/verifier: `docs/development/current/main/phases/phase-29am/README.md`
 
-## Archive
-
-- 旧 backlog（肥大化防止のためアーカイブ）: `docs/development/current/main/phases/phase-29ao/30-Backlog-archive.md`
+Archive: `docs/development/current/main/phases/phase-29ao/30-Backlog-archive.md`