feat(i18n): add multi-language support (ja/ko/vi/ru/zh-TW) with system auto-detection

- Extend AppLanguage to 7 locales: zh-CN, zh-TW, en, ja, ko, vi, ru
- Auto-detect system language via navigator.languages; fallback to English
- Add BCP47 locale mapping for date formatting and sorting
- Create 50 translation JSON files (5 languages × 10 namespaces, 1137 keys each)
- Update language selector with native language names
- Extend locale key parity test to cover all 7 languages (70 assertions)
- Add VNC/RDP desktop, serial terminal, AI agent, port forwarding, and SFTP features
- Add credential encryption, host metrics, session backup crypto, and zmodem bridge
- Update Rust backend: desktop services, host metrics, SSH/SFTP enhancements

src/components/ai/AgentMarkdown.tsx

@@ -0,0 +1,103 @@
+import ReactMarkdown from 'react-markdown'
+import remarkGfm from 'remark-gfm'
+
+interface AgentMarkdownProps {
+  content: string
+  className?: string
+}
+
+/** 简单检测是否含 Markdown 结构（标题/表格/引用/列表/粗体） */
+export function looksLikeMarkdown(text: string): boolean {
+  const t = text.trim()
+  if (!t) return false
+  return (
+    /^#{1,3}\s/m.test(t) ||
+    /^\|.+\|/m.test(t) ||
+    /^>\s/m.test(t) ||
+    /^[-*]\s/m.test(t) ||
+    /^\d+\.\s/m.test(t) ||
+    /\*\*[^*]+\*\*/.test(t) ||
+    /```/.test(t)
+  )
+}
+
+/** Agent 结论富文本：对齐 aiops AgentMarkdown，使用本产品色板 */
+export function AgentMarkdown({ content, className = '' }: AgentMarkdownProps) {
+  return (
+    <div className={`agent-md min-w-0 ${className}`.trim()}>
+      <ReactMarkdown
+        remarkPlugins={[remarkGfm]}
+        components={{
+          h1: ({ children }) => (
+            <h1 className="mb-2 mt-3 text-base font-bold text-content-primary first:mt-0">{children}</h1>
+          ),
+          h2: ({ children }) => (
+            <h2 className="mb-1.5 mt-3 text-sm font-semibold text-content-primary first:mt-0">{children}</h2>
+          ),
+          h3: ({ children }) => (
+            <h3 className="mb-1 mt-2 text-sm font-medium text-content-primary first:mt-0">{children}</h3>
+          ),
+          p: ({ children }) => (
+            <p className="my-1.5 text-xs leading-relaxed text-content-secondary">{children}</p>
+          ),
+          ul: ({ children }) => (
+            <ul className="my-1.5 list-disc space-y-0.5 pl-5 text-xs text-content-secondary">{children}</ul>
+          ),
+          ol: ({ children }) => (
+            <ol className="my-1.5 list-decimal space-y-0.5 pl-5 text-xs text-content-secondary">{children}</ol>
+          ),
+          li: ({ children }) => <li className="leading-relaxed">{children}</li>,
+          strong: ({ children }) => (
+            <strong className="font-semibold text-content-primary">{children}</strong>
+          ),
+          blockquote: ({ children }) => (
+            <blockquote className="my-2 border-l-2 border-accent-blue/50 pl-3 text-xs italic text-txt-muted">
+              {children}
+            </blockquote>
+          ),
+          table: ({ children }) => (
+            <div className="border-dark-700/60 my-2 overflow-x-auto rounded-md border">
+              <table className="w-full border-collapse text-[11px]">{children}</table>
+            </div>
+          ),
+          thead: ({ children }) => <thead className="bg-dark-900/80">{children}</thead>,
+          th: ({ children }) => (
+            <th className="border-dark-700/60 whitespace-nowrap border-b px-2.5 py-1.5 text-left font-medium text-content-primary">
+              {children}
+            </th>
+          ),
+          td: ({ children }) => (
+            <td className="border-dark-700/40 border-b px-2.5 py-1.5 text-content-secondary">{children}</td>
+          ),
+          tr: ({ children }) => <tr className="hover:bg-dark-800/40">{children}</tr>,
+          code: ({ className: codeClass, children }) => {
+            const isBlock = Boolean(codeClass?.includes('language-'))
+            if (isBlock) {
+              return (
+                <pre className="bg-dark-950/60 my-2 overflow-x-auto rounded px-2 py-1.5 text-[11px] text-content-secondary">
+                  <code>{children}</code>
+                </pre>
+              )
+            }
+            return (
+              <code className="bg-dark-800 rounded px-1 py-0.5 text-[11px] text-content-primary">{children}</code>
+            )
+          },
+          hr: () => <hr className="border-dark-700/60 my-3" />,
+          a: ({ href, children }) => (
+            <a
+              href={href}
+              target="_blank"
+              rel="noreferrer"
+              className="text-accent-blue underline-offset-2 hover:underline"
+            >
+              {children}
+            </a>
+          ),
+        }}
+      >
+        {content}
+      </ReactMarkdown>
+    </div>
+  )
+}