docs(05): create phase plan

.planning/STATE.md

@@ -2,9 +2,9 @@
 gsd_state_version: 1.0
 milestone: v1.0
 milestone_name: milestone
-status: completed
-stopped_at: Phase 5 context gathered
-last_updated: "2026-06-09T19:13:07.387Z"
+status: executing
+stopped_at: Phase 5 UI-SPEC approved
+last_updated: "2026-06-09T22:44:55.108Z"
 last_activity: "2026-06-09 -- Phase 04 plan 07 complete (gap-closure: LIST-03 + T-04-08)"
 progress:
   total_phases: 15
@@ -27,7 +27,7 @@ See: .planning/PROJECT.md (updated 2026-06-07)
 
 Phase: 04 (shared-lists-live-sync) — COMPLETE
 Plan: 7 of 7 (all plans complete)
-Status: Phase 04 complete; ready for Phase 05
+Status: Ready to execute
 Last activity: 2026-06-09 -- Phase 04 plan 07 complete (gap-closure: LIST-03 + T-04-08)
 
 Progress: [██████████] 100%
@@ -140,6 +140,6 @@ Recent decisions affecting current work:
 
 ## Session Continuity
 
-Last session: 2026-06-09T19:13:07.379Z
-Stopped at: Phase 5 context gathered
-Resume file: .planning/phases/05-web-push-notifications/05-CONTEXT.md
+Last session: 2026-06-09T22:04:34.038Z
+Stopped at: Phase 5 UI-SPEC approved
+Resume file: .planning/phases/05-web-push-notifications/05-UI-SPEC.md