docs(i18n): English-only by decision — remove the cn shell

The cn language was declared in docs.site.json and mapped in middleware, but
lib/i18n.ts (what fumadocs actually consumes) only ever listed en and there is
zero cn content — a config-vs-runtime drift that made the site look bilingual.
Remove the declaration and the dead zh->cn Accept-Language mapping; keep the
i18n plumbing so a future language is content + one config line.

Verified: docs build passes; with Accept-Language: zh-CN, /docs serves the
English page with no /cn redirect.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: os-zhuang

apps/docs/lib/i18n.ts

@@ -2,10 +2,12 @@ import { defineI18n } from 'fumadocs-core/i18n';
 
 /**
  * i18n Configuration for ObjectStack Documentation
- * 
+ *
  * Supported Languages:
  * - en: English (Default)
- * - cn: Chinese (中文)
+ *
+ * The docs are English-only by decision (2026-07). To add a language later,
+ * list it here and provide content — routing already handles the rest.
  */
 export const i18n = defineI18n({
   defaultLanguage: 'en',

apps/docs/middleware.ts

@@ -19,35 +19,6 @@ function setLocaleCookie(response: NextResponse, locale: string): void {
   });
 }
 
-/**
- * Language code mapping
- * Maps browser language codes to our supported language codes
- */
-const LANGUAGE_MAPPING: Record<string, string> = {
-  'zh': 'cn',      // Chinese -> cn
-  'zh-CN': 'cn',   // Chinese (China) -> cn
-  'zh-TW': 'cn',   // Chinese (Taiwan) -> cn
-  'zh-HK': 'cn',   // Chinese (Hong Kong) -> cn
-};
-
-/**
- * Normalize language code to match our supported languages
- */
-function normalizeLanguage(lang: string): string {
-  // Check direct mapping first
-  if (LANGUAGE_MAPPING[lang]) {
-    return LANGUAGE_MAPPING[lang];
-  }
-  
-  // Check if the base language (without region) is mapped
-  const baseLang = lang.split('-')[0];
-  if (LANGUAGE_MAPPING[baseLang]) {
-    return LANGUAGE_MAPPING[baseLang];
-  }
-  
-  return lang;
-}
-
 /**
  * Get the preferred language from the request
  */
@@ -62,12 +33,9 @@ function getPreferredLanguage(request: NextRequest): string {
   const negotiatorHeaders = Object.fromEntries(request.headers.entries());
   const negotiator = new Negotiator({ headers: negotiatorHeaders });
   const browserLanguages = negotiator.languages();
-  
-  // Normalize browser languages to match our supported languages
-  const normalizedLanguages = browserLanguages.map(normalizeLanguage);
-  
+
   // Find the first match
-  for (const lang of normalizedLanguages) {
+  for (const lang of browserLanguages) {
     if (SUPPORTED_LANGUAGES.includes(lang)) {
       return lang;
     }
@@ -82,9 +50,11 @@ function getPreferredLanguage(request: NextRequest): string {
  * This middleware:
  * - Detects the user's preferred language from browser settings or cookies
  * - Redirects users to the appropriate localized version
- * - For default language (en): keeps URL as "/" (with internal rewrite)
- * - For other languages (cn): redirects to "/cn/"
+ * - For the default language (en): keeps URL as "/" (with internal rewrite)
  * - Stores language preference as a cookie
+ *
+ * The docs are English-only by decision (2026-07); the i18n plumbing stays so a
+ * future language only needs entries in lib/i18n.ts and content, not new routing.
  */
 export default function middleware(request: NextRequest) {
   const { pathname } = request.nextUrl;

content/docs.site.json

@@ -8,7 +8,8 @@
   "i18n": {
     "enabled": true,
     "defaultLanguage": "en",
-    "languages": ["en", "cn"
+    "languages": [
+      "en"
     ]
   },
   "branding": {
@@ -18,7 +19,7 @@
       "dark": "/logo.svg"
     },
     "theme": {
-      "accentColor": "blue", 
+      "accentColor": "blue",
       "radius": "0.5rem"
     }
   },
@@ -34,7 +35,10 @@
         }
       ],
       "socials": [
-        { "platform": "github", "url": "https://github.com/objectstack-ai/spec" }
+        {
+          "platform": "github",
+          "url": "https://github.com/objectstack-ai/spec"
+        }
       ]
     },
     "sidebar": {