feat(mockups): slot 14 voyage with side panel; record verdict on 13

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/DECISIONS.md

@@ -53,3 +53,8 @@ artefacts: kept after merge they go stale and contradict the code, so the spec i
 
 **Decision:** mockup 13 (Curtain call) may use three.js, like 06 and 07. It mocks the frieze → 3D sea →
 frieze → cave transition, which needs the 3D sea. three.js is already a dependency; nothing new is added.
+
+## 2026-10-30 — three.js allowed in mockup 14
+
+**Decision:** mockup 14 (Voyage with side panel) may use three.js; it converges 13's 3D flow with a
+persistent side panel. No new dependency.