- HEXAGONAL_ARCHITECTURE_zh.md becomes the spec: Cockburn/AWS-sourced
standard structure (domain seven-piece layout, file naming rules),
the four-transformation conversion chain with fixed owners and method
names, commands/events design with upgrade triggers, an enforced rule
table, and generic read/write sequence + class diagrams
- FEEDBACK_DESIGN_zh.md is rewritten as the reference-implementation
walkthrough of that spec (commands, exceptions split, _apply mapping,
composition root, updated test map and pitfalls)
- add the definition and dispatch diagrams under docs/assets
