+chinese

.trellis/spec/backend/error-handling.md

@@ -52,3 +52,10 @@ DAOs report database failures without leaking SQL details to JSP pages.
 
 Use concise messages suitable for JSP rendering. For protected operations,
 prefer generic denial messages over exposing permission internals.
+
+For this application, messages rendered into JSP pages should be Simplified
+Chinese. This includes `ServiceResult.message`, field-level validation errors,
+flash messages set by Servlet controllers, and display names returned by entity
+helpers. Keep log-only diagnostics, exception types, stored enum codes, request
+parameter names, and database values unchanged unless a separate contract change
+requires it.

.trellis/spec/frontend/component-guidelines.md

@@ -23,6 +23,19 @@ the reusable UI units.
 
 ---
 
+## Interface Copy
+
+- Render user-visible JSP copy in Simplified Chinese, including navigation,
+  headings, form labels, buttons, table headers, empty states, and accessible
+  labels.
+- Keep machine-readable values unchanged: URLs, request parameter names, CSS
+  classes, Java identifiers, enum codes, database values, and servlet names stay
+  in their existing code form.
+- Translate display helper output and controller/service messages when they are
+  rendered into JSP pages.
+
+---
+
 ## Forms
 
 - Forms should post to Servlet controller endpoints, not directly to DAOs or