docs(32): create phase plans for setup sharing system

4 plans in 3 waves:
- Wave 1: Schema migration (isPublic→visibility) + shares table
- Wave 2: Share link service + API routes
- Wave 3: Share modal UI + shared setup viewer

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.planning/ROADMAP.md

@@ -173,7 +173,13 @@ Plans:
 **Requirements**: TBD (discuss phase)
 **Success Criteria** (what must be TRUE):
   TBD (discuss phase)
-**Plans**: TBD
+**Plans**: 4 plans
+
+Plans:
+- [ ] 32-01-PLAN.md — Schema migration (isPublic to visibility) + shares table + full-stack update
+- [ ] 32-02-PLAN.md — Share link service, API routes, and short URL redirect
+- [ ] 32-03-PLAN.md — Share modal UI component with visibility picker and link management
+- [ ] 32-04-PLAN.md — Shared setup viewer with token detection and read-only mode
 **UI hint**: yes
 
 ### Phase 33: Currency System
@@ -227,7 +233,7 @@ Plans:
 | 29. Image Presentation | v2.2 | 5/5 | Complete   | 2026-04-13 |
 | 30. Onboarding Redesign | v2.2 | 3/3 | Complete    | 2026-04-12 |
 | 31. Mobile Polish | v2.2 | 2/2 | Complete    | 2026-04-12 |
-| 32. Setup Sharing System | v2.3 | TBD | Pending | — |
+| 32. Setup Sharing System | v2.3 | 0/4 | Planned | — |
 | 33. Currency System | v2.3 | TBD | Pending | — |
 | 34. i18n Foundation | v2.3 | TBD | Pending | — |