Clarify slash command documentation contract

docs/ARCHITECTURE.md

@@ -214,7 +214,8 @@ src/
 Files kept small by design: the largest module under `cli/ui/` is 2K
 lines (App.tsx), every handler under `slash/handlers/` is ≤200 lines,
 every hook under `cli/ui/` is ≤310 lines. Adding a new slash command
-means editing one handler file and one registry line.
+means updating its handler, registry entry, localized help copy, and any
+public command reference that surfaces the slash list.
 
 ## Design evolution
 

docs/arch-i18n.js

@@ -111,7 +111,7 @@
 
     "mod.title": "Module layout",
     "mod.note":
-      "Files kept small by design: the largest module under <code>cli/ui/</code> is 2K lines (App.tsx), every handler under <code>slash/handlers/</code> is ≤200 lines, every hook under <code>cli/ui/</code> is ≤310 lines. Adding a new slash command means editing one handler file and one registry line.",
+      "Files kept small by design: the largest module under <code>cli/ui/</code> is 2K lines (App.tsx), every handler under <code>slash/handlers/</code> is ≤200 lines, every hook under <code>cli/ui/</code> is ≤310 lines. Adding a new slash command means updating its handler, registry entry, localized help copy, and any public command reference that surfaces the slash list.",
 
     "evo.title": "Design evolution",
 
@@ -231,7 +231,7 @@
 
     "mod.title": "模块布局",
     "mod.note":
-      "文件故意保持精简：<code>cli/ui/</code> 下最大的模块是 2K 行（App.tsx），<code>slash/handlers/</code> 下每个 handler ≤200 行，<code>cli/ui/</code> 下每个 hook ≤310 行。新增斜杠命令只需改一个 handler 文件和一行注册。",
+      "文件故意保持精简：<code>cli/ui/</code> 下最大的模块是 2K 行（App.tsx），<code>slash/handlers/</code> 下每个 handler ≤200 行，<code>cli/ui/</code> 下每个 hook ≤310 行。新增斜杠命令需要同步更新 handler、注册表、本地化帮助文案，以及任何公开展示斜杠列表的命令参考。",
 
     "evo.title": "设计演进",
 

docs/architecture.html

@@ -475,7 +475,8 @@ <h2 data-i18n="mod.title">Module layout</h2>
               Files kept small by design: the largest module under <code>cli/ui/</code> is
               2K lines (App.tsx), every handler under <code>slash/handlers/</code> is
               ≤200 lines, every hook under <code>cli/ui/</code> is ≤310 lines. Adding a
-              new slash command means editing one handler file and one registry line.
+              new slash command means updating its handler, registry entry, localized
+              help copy, and any public command reference that surfaces the slash list.
             </p>
           </section>