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

shared/types/session.types.ts

@@ -6,6 +6,9 @@
 // 认证方式
 export type AuthType = 'password' | 'key' | 'agent'
 
+/** Persisted session protocol. Missing/undefined means SSH (legacy rows). */
+export type SessionProtocol = 'ssh' | 'rdp' | 'vnc'
+
 // 代理类型
 export type ProxyType = 'none' | 'http' | 'socks5'
 
@@ -65,9 +68,12 @@ export interface Session {
   port: number
   username: string
   authType: AuthType
+  /** Defaults to ssh when omitted (legacy sessions). */
+  protocol?: SessionProtocol
   password?: string        // 加密存储
-  privateKey?: string      // 私钥路径或内容
-  passphrase?: string      // 私钥密码
+  /** 私钥路径或 PEM 正文；落盘时由 Rust 加密 */
+  privateKey?: string
+  passphrase?: string      // 私钥密码（加密存储）
   proxy?: ProxyConfig      // 代理配置
   /** 连接成功后自动执行的启动命令 */
   startupCommand?: string
@@ -79,6 +85,20 @@ export interface Session {
   jumpHost?: JumpHostConfig
   /** 内联多跳板链 */
   jumpHosts?: JumpHostConfig[]
+  /** RDP domain (optional). */
+  domain?: string
+  /** RDP security mode. */
+  security?: 'nla' | 'tls' | 'rdp' | 'auto'
+  /** Desktop resolution hint (RDP/VNC). */
+  width?: number
+  height?: number
+  /**
+   * Detected or manual remote OS / distro icon id
+   * (ubuntu, debian, windows, vnc, linux, …).
+   */
+  distro?: string
+  /** Human-readable OS from PRETTY_NAME (e.g. Ubuntu 24.04.4 LTS). */
+  osPrettyName?: string
   group?: string
   tags?: string[]
   createdAt?: number
@@ -92,6 +112,7 @@ export interface SessionCreateRequest {
   port: number
   username: string
   authType: AuthType
+  protocol?: SessionProtocol
   password?: string
   privateKey?: string
   passphrase?: string
@@ -101,6 +122,11 @@ export interface SessionCreateRequest {
   jumpSessionIds?: string[]
   jumpHost?: JumpHostConfig
   jumpHosts?: JumpHostConfig[]
+  domain?: string
+  security?: 'nla' | 'tls' | 'rdp' | 'auto'
+  width?: number
+  height?: number
+  distro?: string
   group?: string
   tags?: string[]
 }