feat(proxy): HTTP/SOCKS5 代理支持，按会话独立配置 | 15 files +483/-23 | 96/96 tests passing

功能:
- 代理类型定义 (ProxyType, ProxyConfig)
- 代理工具函数 (验证、解析、构建URL) + 24 测试
- SSH 连接通过 HTTP CONNECT / SOCKS5 隧道
- 数据库 proxy 列持久化 (JSON)
- SessionDialog 代理配置 UI (可折叠面板)
- 连接池传递 proxy 到 IPC
- sessionStore 类型添加 proxy 支持

electron/services/ssh-service.ts

@@ -5,6 +5,7 @@ import * as net from 'net'
 import * as fs from 'fs'
 import * as os from 'os'
 import * as path from 'path'
+import type { ProxyConfig } from '../../shared/types/session.types'
 
 const logger = createLogger('SSHService')
 
@@ -39,6 +40,7 @@ export interface SSHConfig {
   agent?: string
   readyTimeout?: number
   keepaliveInterval?: number
+  proxy?: ProxyConfig
 }
 
 export interface Connection {
@@ -141,8 +143,7 @@ export class SSHService {
         return
       }
 
-      debug('>>> Starting SSH client.connect...')
-      client.connect({
+      const sshConnectOpts = {
         host: config.host,
         port: config.port || 22,
         username: config.username,
@@ -152,6 +153,246 @@ export class SSHService {
         agent: config.agent,
         readyTimeout: config.readyTimeout || 20000,
         keepaliveInterval: config.keepaliveInterval || 60000,
+      }
+
+      // 如果配置了代理，先通过代理建立隧道
+      if (config.proxy && config.proxy.type !== 'none' && config.proxy.host) {
+        debug('>>> Connecting through proxy:', config.proxy.type, config.proxy.host, config.proxy.port)
+        this.connectThroughProxy(config.proxy, config.host, config.port || 22)
+          .then((socket) => {
+            debug('>>> Proxy tunnel established, starting SSH handshake')
+            client.connect({
+              ...sshConnectOpts,
+              sock: socket,
+            })
+          })
+          .catch((err) => {
+            connection.status = 'error'
+            this.connections.delete(connectionId)
+            logger.error(`Proxy connection failed for ${connectionId}:`, err)
+            reject(new Error(`代理连接失败: ${err.message}`))
+          })
+      } else {
+        debug('>>> Starting SSH client.connect (direct)...')
+        client.connect(sshConnectOpts)
+      }
+    })
+  }
+
+  /**
+   * 通过代理建立 TCP 隧道
+   * 支持 HTTP CONNECT 和 SOCKS5
+   */
+  private connectThroughProxy(
+    proxy: ProxyConfig,
+    targetHost: string,
+    targetPort: number
+  ): Promise<net.Socket> {
+    if (proxy.type === 'http') {
+      return this.connectThroughHttpProxy(proxy, targetHost, targetPort)
+    } else if (proxy.type === 'socks5') {
+      return this.connectThroughSocks5Proxy(proxy, targetHost, targetPort)
+    }
+    return Promise.reject(new Error(`不支持的代理类型: ${proxy.type}`))
+  }
+
+  /**
+   * HTTP CONNECT 代理隧道
+   */
+  private connectThroughHttpProxy(
+    proxy: ProxyConfig,
+    targetHost: string,
+    targetPort: number
+  ): Promise<net.Socket> {
+    return new Promise((resolve, reject) => {
+      const socket = new net.Socket()
+      const connectTimeout = setTimeout(() => {
+        socket.destroy()
+        reject(new Error('代理连接超时'))
+      }, 15000)
+
+      socket.connect(proxy.port, proxy.host, () => {
+        clearTimeout(connectTimeout)
+        debug('>>> Connected to HTTP proxy:', proxy.host, proxy.port)
+
+        // 构建 CONNECT 请求
+        let connectRequest = `CONNECT ${targetHost}:${targetPort} HTTP/1.1\r\nHost: ${targetHost}:${targetPort}\r\n`
+        
+        // 代理认证
+        if (proxy.username) {
+          const credentials = Buffer.from(`${proxy.username}:${proxy.password || ''}`).toString('base64')
+          connectRequest += `Proxy-Authorization: Basic ${credentials}\r\n`
+        }
+        connectRequest += '\r\n'
+
+        socket.write(connectRequest)
+
+        let responseBuffer = ''
+        const onData = (data: Buffer) => {
+          responseBuffer += data.toString()
+          
+          // 检查是否收到完整 HTTP 响应头
+          const headerEnd = responseBuffer.indexOf('\r\n\r\n')
+          if (headerEnd === -1) return
+
+          socket.removeListener('data', onData)
+          const header = responseBuffer.substring(0, headerEnd)
+          
+          // 解析状态码
+          const statusMatch = header.match(/^HTTP\/\d\.\d\s+(\d+)\s+(.*)/)
+          if (!statusMatch) {
+            socket.destroy()
+            reject(new Error('代理返回无效响应'))
+            return
+          }
+
+          const statusCode = parseInt(statusMatch[1], 10)
+          if (statusCode >= 200 && statusCode < 300) {
+            debug('>>> HTTP proxy tunnel established')
+            resolve(socket)
+          } else {
+            socket.destroy()
+            reject(new Error(`代理拒绝连接: ${statusCode} ${statusMatch[2]}`))
+          }
+        }
+
+        socket.on('data', onData)
+        socket.on('error', (err) => {
+          clearTimeout(connectTimeout)
+          reject(new Error(`代理连接错误: ${err.message}`))
+        })
+      })
+
+      socket.on('error', (err) => {
+        clearTimeout(connectTimeout)
+        reject(new Error(`无法连接代理服务器: ${err.message}`))
+      })
+    })
+  }
+
+  /**
+   * SOCKS5 代理隧道
+   */
+  private connectThroughSocks5Proxy(
+    proxy: ProxyConfig,
+    targetHost: string,
+    targetPort: number
+  ): Promise<net.Socket> {
+    return new Promise((resolve, reject) => {
+      const socket = new net.Socket()
+      const connectTimeout = setTimeout(() => {
+        socket.destroy()
+        reject(new Error('SOCKS5 代理连接超时'))
+      }, 15000)
+
+      socket.connect(proxy.port, proxy.host, () => {
+        clearTimeout(connectTimeout)
+        debug('>>> Connected to SOCKS5 proxy:', proxy.host, proxy.port)
+
+        // SOCKS5 握手阶段 1: 认证方法协商
+        let authMethods: Buffer
+        if (proxy.username) {
+          // 支持无认证(0x00)和用户名密码认证(0x02)
+          authMethods = Buffer.from([0x05, 0x02, 0x00, 0x02])
+        } else {
+          // 仅支持无认证
+          authMethods = Buffer.from([0x05, 0x01, 0x00])
+        }
+        socket.write(authMethods)
+
+        const handleHandshake = (data: Buffer) => {
+          if (data.length < 2) {
+            socket.destroy()
+            reject(new Error('SOCKS5 握手响应无效'))
+            return
+          }
+
+          const version = data[0]
+          const method = data[1]
+
+          if (version !== 0x05) {
+            socket.destroy()
+            reject(new Error('不是 SOCKS5 代理'))
+            return
+          }
+
+          if (method === 0x02 && proxy.username) {
+            // 用户名密码认证
+            socket.removeListener('data', handleHandshake)
+            const userBuf = Buffer.from(proxy.username)
+            const passBuf = Buffer.from(proxy.password || '')
+            const authBuf = Buffer.alloc(3 + userBuf.length + passBuf.length)
+            authBuf[0] = 0x01 // 认证协商版本
+            authBuf[1] = userBuf.length
+            userBuf.copy(authBuf, 2)
+            authBuf[2 + userBuf.length] = passBuf.length
+            passBuf.copy(authBuf, 3 + userBuf.length)
+            socket.write(authBuf)
+
+            socket.once('data', (authResp: Buffer) => {
+              if (authResp.length < 2 || authResp[1] !== 0x00) {
+                socket.destroy()
+                reject(new Error('SOCKS5 认证失败'))
+                return
+              }
+              sendConnectRequest()
+            })
+          } else if (method === 0x00) {
+            // 无需认证
+            socket.removeListener('data', handleHandshake)
+            sendConnectRequest()
+          } else {
+            socket.destroy()
+            reject(new Error('SOCKS5 不支持此认证方法'))
+            return
+          }
+        }
+
+        const sendConnectRequest = () => {
+          // SOCKS5 CONNECT 请求
+          const hostBuf = Buffer.from(targetHost)
+          // VER(1) + CMD(1) + RSV(1) + ATYP(1) + DOMAIN_LEN(1) + DOMAIN + PORT(2)
+          const connectBuf = Buffer.alloc(4 + 1 + hostBuf.length + 2)
+          connectBuf[0] = 0x05 // SOCKS5
+          connectBuf[1] = 0x01 // CONNECT
+          connectBuf[2] = 0x00 // 保留
+          connectBuf[3] = 0x03 // 域名类型
+          connectBuf[4] = hostBuf.length
+          hostBuf.copy(connectBuf, 5)
+          connectBuf.writeUInt16BE(targetPort, 5 + hostBuf.length)
+          socket.write(connectBuf)
+
+          socket.once('data', (connectResp: Buffer) => {
+            if (connectResp.length < 4 || connectResp[1] !== 0x00) {
+              const errorCode = connectResp.length >= 2 ? connectResp[1] : -1
+              const errorMessages: Record<number, string> = {
+                0x01: 'SOCKS5 服务器错误',
+                0x02: 'SOCKS5 连接不允许',
+                0x03: 'SOCKS5 网络不可达',
+                0x04: 'SOCKS5 主机不可达',
+                0x05: 'SOCKS5 连接拒绝',
+                0x06: 'SOCKS5 TTL 过期',
+                0x07: 'SOCKS5 不支持的命令',
+                0x08: 'SOCKS5 地址类型不支持',
+              }
+              socket.destroy()
+              reject(new Error(errorMessages[errorCode] || `SOCKS5 连接失败 (${errorCode})`))
+              return
+            }
+            debug('>>> SOCKS5 proxy tunnel established')
+            resolve(socket)
+          })
+        }
+
+        socket.on('data', handleHandshake)
+        socket.on('error', (err) => {
+          reject(new Error(`SOCKS5 代理错误: ${err.message}`))
+        })
+      })
+
+      socket.on('error', (err) => {
+        clearTimeout(connectTimeout)
+        reject(new Error(`无法连接 SOCKS5 代理: ${err.message}`))
       })
     })
   }