docs(18): create phase plan for global items and public profiles

.planning/ROADMAP.md

@@ -177,7 +177,13 @@ Plans:
   3. A global item page shows basic info and how many users own it
   4. User can edit their profile (display name, avatar, bio) and view their own public profile page
   5. User can toggle a setup between public and private; public setups are viewable by anyone without logging in and appear on the owner's public profile
-**Plans**: TBD
+**Plans:** 5 plans
+Plans:
+- [ ] 18-01-PLAN.md — Schema foundation: globalItems, itemGlobalLinks, user profile columns, setup isPublic, Zod schemas, types, seed data
+- [ ] 18-02-PLAN.md — Global item backend: service (search, owner count, link/unlink), routes, seed script, tests
+- [ ] 18-03-PLAN.md — Profile and sharing backend: profile service, public profile/setup routes, auth middleware updates, tests
+- [ ] 18-04-PLAN.md — Global item client: catalog browse/search page, detail page, link-to-global-item UI
+- [ ] 18-05-PLAN.md — Profile and sharing client: profile edit in settings, public profile page, setup visibility toggle
 **UI hint**: yes
 
 ## Progress
@@ -201,4 +207,4 @@ Plans:
 | 15. External Authentication | v2.0 | 0/? | Not started | - |
 | 16. Multi-User Data Model | v2.0 | 2/4 | Complete    | 2026-04-05 |
 | 17. Object Storage | v2.0 | 3/3 | Complete    | 2026-04-05 |
-| 18. Global Items & Public Profiles | v2.0 | 0/? | Not started | - |
+| 18. Global Items & Public Profiles | v2.0 | 0/5 | Not started | - |