chore: record journal

.trellis/workspace/dingkang/journal-1.md

@@ -404,3 +404,24 @@ Added configurable GLB budgets with documented exceptions, shared budget evaluat
 ### Status
 
 [OK] **Completed**
+
+
+## Session 20: Split area preview orchestration
+
+**Date**: 2026-08-04
+**Task**: Split area preview orchestration
+**Branch**: `main`
+
+### Summary
+
+Extracted preview route, vehicle glTF, and HTML/runtime assembly from build-area into focused modules; added preview asset tests and verified nantaizi preview, diagnostics, and quality gate.
+
+### Git Commits
+
+| Hash | Message |
+|------|---------|
+| `396df51` | (see git log) |
+
+### Status
+
+[OK] **Completed**