docs(27): add phase 27 to roadmap

.planning/ROADMAP.md

@@ -126,6 +126,19 @@ Plans:
 - [x] 26-03-PLAN.md — Landing page UI and PublicSetupCard enhancement
 **UI hint**: yes
 
+### Phase 27: Top Nav Restructure & Search Bar Rethink
+**Goal**: Replace the minimal TotalsBar with a persistent top navigation bar (logo, section links, catalog search, user avatar) and move mobile navigation to a bottom tab bar — elevating Setups to top-level and removing the landing page hero
+**Depends on**: Phase 26
+**Requirements**: TBD
+**Success Criteria** (what must be TRUE):
+  1. A persistent top nav bar shows logo, Home/Collection/Setups links, catalog search, and user avatar on desktop
+  2. Clicking Collection or Setups while anonymous triggers AuthPromptModal instead of navigating
+  3. On mobile, navigation appears as a fixed bottom tab bar with Home, Collection, Setups, and Search icons
+  4. The landing page no longer has a hero section — content starts with Popular Setups
+  5. Setups has its own top-level route accessible from the nav bar, not nested in Collection tabs
+**Plans**: TBD
+**UI hint**: yes
+
 ## Progress
 
 | Phase | Milestone | Plans Complete | Status | Completed |