docs(04-02): complete visual polish plan

- Add 04-02-SUMMARY.md with animation and error handler results
- Update STATE.md with progress, decisions, metrics
- Update ROADMAP.md with plan progress
- Mark PLSH-01 through PLSH-05 complete in REQUIREMENTS.md

.planning/STATE.md

@@ -2,15 +2,15 @@
 gsd_state_version: 1.0
 milestone: v1.0
 milestone_name: milestone
-status: verifying
-stopped_at: Phase 4 context gathered (assumptions mode)
-last_updated: "2026-03-29T16:06:03.859Z"
+status: executing
+stopped_at: Completed 04-02-PLAN.md
+last_updated: "2026-03-29T16:17:26.933Z"
 last_activity: 2026-03-29
 progress:
   total_phases: 4
   completed_phases: 3
-  total_plans: 15
-  completed_plans: 15
+  total_plans: 19
+  completed_plans: 17
   percent: 0
 ---
 
@@ -21,13 +21,13 @@ progress:
 See: .planning/PROJECT.md (updated 2026-03-29)
 
 **Core value:** Das Kind übt freiwillig weiter, weil es wissen will, was als Nächstes im Wald erscheint — nicht weil es Punkte sammelt.
-**Current focus:** Phase 03 — komplettes-spielerlebnis
+**Current focus:** Phase 04 — polish-audio
 
 ## Current Position
 
-Phase: 4
-Plan: Not started
-Status: Phase complete — ready for verification
+Phase: 04 (polish-audio) — EXECUTING
+Plan: 2 of 4
+Status: Ready to execute
 Last activity: 2026-03-29
 
 Progress: [░░░░░░░░░░] 0%
@@ -67,6 +67,7 @@ Progress: [░░░░░░░░░░] 0%
 | Phase 03 P05 | 2min | 2 tasks | 4 files |
 | Phase 03 P02 | 4min | 2 tasks | 6 files |
 | Phase 03 P04 | 3min | 2 tasks | 4 files |
+| Phase 04 P02 | 2min | 2 tasks | 3 files |
 
 ## Accumulated Context
 
@@ -101,6 +102,8 @@ Recent decisions affecting current work:
 - [Phase 03]: Discover phase skips space key; review pulls 2 words from each of last 2-3 levels
 - [Phase 03]: Pre-generation uses fire-and-forget pattern: startPreGeneration() at lesson start, awaited on reward screen
 - [Phase 03]: Progress migration function ensures backward compat with older IndexedDB data
+- [Phase 04]: Stardust particles use box-shadow on pseudo-elements for 6 total sparkle points
+- [Phase 04]: Error overlay uses tree emoji and German child-friendly message
 
 ### Pending Todos
 
@@ -112,6 +115,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-29T16:06:03.853Z
-Stopped at: Phase 4 context gathered (assumptions mode)
-Resume file: .planning/phases/04-polish-audio/04-CONTEXT.md
+Last session: 2026-03-29T16:17:26.927Z
+Stopped at: Completed 04-02-PLAN.md
+Resume file: None