refactor(pages): one about page per language, no R2 cache by default

- app/[lang]/about/page.tsx renders en, zh and ja (zh-Hant falls back
  to zh) from one JSX tree with per-language texts and generateMetadata;
  delete the cn/ and ja/ copies and redirect their old URLs
- app/[lang]/layout.tsx: use hasLocale, an OG locale table, and real
  zh/ja title and description
- components/icons/github.tsx replaces react-icons and lucide's
  deprecated Github icon
- quota-limit-toast: read the dictionary keys directly, shadow-float
- Cloudflare: defineCloudflareConfig({}) without R2, no r2_buckets, no
  dev-time OpenNext init, cf-typegen script removed,
  @opennextjs/cloudflare moves to devDependencies, docs updated

components/icons/github.tsx

@@ -0,0 +1,13 @@
+// GitHub mark as an inline SVG, so no icon package is needed for one icon
+export function GitHubIcon({ className }: { className?: string }) {
+    return (
+        <svg
+            viewBox="0 0 16 16"
+            fill="currentColor"
+            aria-hidden="true"
+            className={className}
+        >
+            <path d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47 7.59.4.07.55-.17.55-.38 0-.19-.01-.82-.01-1.49-2.01.37-2.53-.49-2.69-.94-.09-.23-.48-.94-.82-1.13-.28-.15-.68-.52-.01-.53.63-.01 1.08.58 1.23.82.72 1.21 1.87.87 2.33.66.07-.52.28-.87.51-1.07-1.78-.2-3.64-.89-3.64-3.95 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12 0 0 .67-.21 2.2.82.64-.18 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 2.12.51.56.82 1.27.82 2.15 0 3.07-1.87 3.75-3.65 3.95.29.25.54.73.54 1.48 0 1.07-.01 1.93-.01 2.2 0 .21.15.46.55.38A8.013 8.013 0 0016 8c0-4.42-3.58-8-8-8z" />
+        </svg>
+    )
+}

components/quota-limit-toast.tsx

@@ -2,7 +2,7 @@
 
 import { Coffee, Settings, X } from "lucide-react"
 import type React from "react"
-import { FaGithub } from "react-icons/fa"
+import { GitHubIcon } from "@/components/icons/github"
 import { useDictionary } from "@/hooks/use-dictionary"
 import { formatMessage } from "@/lib/i18n/utils"
 
@@ -28,16 +28,10 @@ export function QuotaLimitToast({
         n >= 1000 ? `${(n / 1000).toFixed(1)}k` : n.toString()
 
     const quotaMessage = isTokenLimit
-        ? isSelfHosted
-            ? (dict.quota.messageTokenSelfHosted ?? dict.quota.messageToken)
-            : dict.quota.messageToken
-        : isSelfHosted
-          ? (dict.quota.messageApiSelfHosted ?? dict.quota.messageApi)
-          : dict.quota.messageApi
+        ? dict.quota.messageToken
+        : dict.quota.messageApi
 
-    const tipHtml = isSelfHosted
-        ? (dict.quota.tipSelfHosted ?? dict.quota.tip)
-        : dict.quota.tip
+    const tipHtml = isSelfHosted ? dict.quota.tipSelfHosted : dict.quota.tip
 
     const handleKeyDown = (e: React.KeyboardEvent) => {
         if (e.key === "Escape") {
@@ -52,7 +46,7 @@ export function QuotaLimitToast({
             aria-live="polite"
             tabIndex={0}
             onKeyDown={handleKeyDown}
-            className="relative w-[400px] overflow-hidden rounded-xl border border-border/50 bg-card p-5 shadow-soft animate-message-in"
+            className="relative w-[400px] overflow-hidden rounded-xl border border-border/50 bg-card p-5 shadow-float animate-message-in"
         >
             {/* Close button */}
             <button
@@ -115,7 +109,7 @@ export function QuotaLimitToast({
                             rel="noopener noreferrer"
                             className="inline-flex items-center gap-1.5 px-3 py-1.5 text-xs font-medium rounded-lg border border-border text-foreground hover:bg-muted transition-colors"
                         >
-                            <FaGithub className="w-3.5 h-3.5" />
+                            <GitHubIcon className="w-3.5 h-3.5" />
                             {dict.quota.selfHost}
                         </a>
                         <a

components/settings-dialog.tsx

@@ -1,5 +1,4 @@
 import {
-    Github,
     Info,
     Monitor,
     Moon,
@@ -13,6 +12,7 @@ import { usePathname, useRouter, useSearchParams } from "next/navigation"
 import { useEffect, useState } from "react"
 import { toast } from "sonner"
 import { useChatEngine } from "@/components/chat/chat-engine"
+import { GitHubIcon } from "@/components/icons/github"
 import { ModelConfigDialog } from "@/components/model-config-dialog"
 import { SettingsHeader } from "@/components/settings/settings-header"
 import { Button } from "@/components/ui/button"
@@ -510,7 +510,7 @@ function AboutTab() {
     const lang = pathname.split("/").filter(Boolean)[0] || i18n.defaultLocale
     const showAbout = process.env.NEXT_PUBLIC_SHOW_ABOUT_AND_NOTICE === "true"
     const isSelfHosted = process.env.NEXT_PUBLIC_SELFHOSTED === "true"
-    const aboutPath = `/${lang}/about${lang === "zh" ? "/cn" : lang === "ja" ? "/ja" : ""}`
+    const aboutPath = `/${lang}/about`
 
     return (
         <div className="space-y-5">
@@ -553,7 +553,7 @@ function AboutTab() {
                     rel="noopener noreferrer"
                     className="inline-flex h-8 items-center gap-1.5 rounded-lg border border-border px-3 text-xs text-muted-foreground hover:text-foreground"
                 >
-                    <Github className="size-3.5" />
+                    <GitHubIcon className="size-3.5" />
                     GitHub
                 </a>
                 {showAbout && (