docs(04-ux-improvements): create phase plan

.planning/ROADMAP.md

@@ -75,9 +75,14 @@ Plans:
   4. A badge/counter showing pending update count is always visible; the browser tab title reflects it (e.g., "DiunDash (3)")
   5. New updates arriving during active polling trigger a visible in-page toast, and updates seen for the first time since the user's last visit are visually highlighted
   6. The light/dark theme toggle is available and respects system preference; the drag handle for tag reordering is always visible without hover
-**Plans**: TBD
+**Plans**: 3 plans
 **UI hint**: yes
 
+Plans:
+- [ ] 04-01-PLAN.md — Backend bulk dismiss: extend Store interface with AcknowledgeAll + AcknowledgeByTag, implement in both stores, add HTTP handlers and tests
+- [ ] 04-02-PLAN.md — Frontend search/filter/sort controls, theme toggle, drag handle visibility fix
+- [ ] 04-03-PLAN.md — Frontend bulk dismiss UI, update indicators (badge, tab title, toast, new-since-last-visit highlight)
+
 ## Progress
 
 **Execution Order:**
@@ -88,4 +93,4 @@ Phases execute in numeric order: 1 → 2 → 3 → 4
 | 1. Data Integrity | 0/2 | Not started | - |
 | 2. Backend Refactor | 2/2 | Complete   | 2026-03-24 |
 | 3. PostgreSQL Support | 0/2 | Not started | - |
-| 4. UX Improvements | 0/? | Not started | - |
+| 4. UX Improvements | 0/3 | Not started | - |