feat(pairing): implement core pairing logic module

Add adapters/common/pairing.ts with generatePairingCode(), isPaired(),
and tryPair() — one-time-use 6-char code flow with atomic config writes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

adapters/common/pairing.ts

@@ -0,0 +1,107 @@
+/**
+ * 配对核心逻辑
+ *
+ * - generatePairingCode(): 生成 6 位安全配对码
+ * - isPaired(): 检查用户是否已配对（pairedUsers + allowedUsers 并集）
+ * - tryPair(): 验证配对码，成功则写入 pairedUsers 并清除 code
+ */
+
+import * as fs from 'node:fs'
+import * as os from 'node:os'
+import * as path from 'node:path'
+import * as crypto from 'node:crypto'
+import type { PairedUser, PairingState } from './config.js'
+
+const SAFE_ALPHABET = 'ABCDEFGHJKMNPQRSTUVWXYZ23456789' // 排除 0/O/1/I/L
+const CODE_LENGTH = 6
+const CODE_TTL_MS = 60 * 60 * 1000 // 60 minutes
+
+function getConfigPath(): string {
+  const configDir = process.env.CLAUDE_CONFIG_DIR || path.join(os.homedir(), '.claude')
+  return path.join(configDir, 'adapters.json')
+}
+
+function readConfigFile(): Record<string, any> {
+  try {
+    return JSON.parse(fs.readFileSync(getConfigPath(), 'utf-8'))
+  } catch {
+    return {}
+  }
+}
+
+function writeConfigFile(data: Record<string, any>): void {
+  const filePath = getConfigPath()
+  const dir = path.dirname(filePath)
+  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true })
+  const tmp = `${filePath}.tmp.${Date.now()}`
+  fs.writeFileSync(tmp, JSON.stringify(data, null, 2) + '\n', 'utf-8')
+  fs.renameSync(tmp, filePath)
+}
+
+export function generatePairingCode(): string {
+  let code = ''
+  for (let i = 0; i < CODE_LENGTH; i++) {
+    code += SAFE_ALPHABET[crypto.randomInt(SAFE_ALPHABET.length)]
+  }
+  return code
+}
+
+/** 检查用户是否已配对（pairedUsers + allowedUsers 并集） */
+export function isPaired(
+  platform: 'telegram' | 'feishu',
+  userId: string | number,
+  config: Record<string, any>,
+): boolean {
+  const platformConfig = config[platform] ?? {}
+  const allowedUsers: (string | number)[] = platformConfig.allowedUsers ?? []
+  const pairedUsers: PairedUser[] = platformConfig.pairedUsers ?? []
+
+  // allowedUsers 非空时检查
+  if (allowedUsers.length > 0 && allowedUsers.includes(userId)) return true
+  // allowedUsers 为空且 pairedUsers 也为空 => 旧行为（允许所有人）
+  if (pairedUsers.length === 0 && allowedUsers.length === 0) return true
+
+  return pairedUsers.some((p) => String(p.userId) === String(userId))
+}
+
+/**
+ * 尝试配对：验证消息文本是否匹配当前有效配对码。
+ * 成功则写入 pairedUsers 并清除 pairing.code，返回 true。
+ */
+export function tryPair(
+  messageText: string,
+  senderInfo: { userId: string | number; displayName: string },
+  platform: 'telegram' | 'feishu',
+): boolean {
+  const file = readConfigFile()
+  const pairing: PairingState = file.pairing ?? { code: null, expiresAt: null, createdAt: null }
+
+  // 检查配对码是否有效
+  if (!pairing.code || !pairing.expiresAt) return false
+  if (Date.now() > pairing.expiresAt) return false
+
+  // 比较（忽略大小写和空格）
+  const input = messageText.trim().toUpperCase()
+  if (input !== pairing.code.toUpperCase()) return false
+
+  // 配对成功：写入 pairedUsers
+  const platformConfig = file[platform] ?? {}
+  const pairedUsers: PairedUser[] = platformConfig.pairedUsers ?? []
+
+  // 避免重复
+  const exists = pairedUsers.some((p) => String(p.userId) === String(senderInfo.userId))
+  if (!exists) {
+    pairedUsers.push({
+      userId: senderInfo.userId,
+      displayName: senderInfo.displayName,
+      pairedAt: Date.now(),
+    })
+  }
+
+  // 更新 config
+  file[platform] = { ...platformConfig, pairedUsers }
+  file.pairing = { code: null, expiresAt: null, createdAt: null } // 一次性使用
+  writeConfigFile(file)
+
+  return true
+}