docs(21): create phase plan — 3 plans across 2 waves

.planning/ROADMAP.md

@@ -217,7 +217,11 @@ Plans:
   3. Thread candidates navigate to detail pages instead of opening slide-out panels
   4. Item slide-out panel and candidate slide-out panel are removed from the root layout
   5. No visual distinction between reference items and standalone items — same layout, some fields may be empty
-**Plans**: TBD
+**Plans:** 3 plans
+Plans:
+- [ ] 21-01-PLAN.md — Item detail page with edit mode + catalog detail page enhancement
+- [ ] 21-02-PLAN.md — Candidate detail page with edit mode + add-candidate modal
+- [ ] 21-03-PLAN.md — Rewire card navigation + remove slide-out panels + UIStore cleanup
 **UI hint**: yes
 
 ### Phase 22: Add-from-Catalog & Thread Integration
@@ -266,6 +270,6 @@ Plans:
 | 18. Global Items & Public Profiles | v2.0 | 4/5 | Complete    | 2026-04-05 |
 | 19. Reference Item Model & Tags Schema | v2.0 | 3/3 | Complete    | 2026-04-05 |
 | 20. FAB & Full-Screen Catalog Search | v2.0 | 2/2 | Complete    | 2026-04-06 |
-| 21. Item & Catalog Detail Pages | v2.0 | 0/? | Not started | - |
+| 21. Item & Catalog Detail Pages | v2.0 | 0/3 | Planning | - |
 | 22. Add-from-Catalog & Thread Integration | v2.0 | 0/? | Not started | - |
 | 23. Manual Entry Fallback | v2.0 | 0/? | Not started | - |