feat(cliproxy): add --add flag and nickname support for multi-account auth

- Add `--add` flag to skip confirm prompt when adding accounts
- Add confirm prompt when accounts exist and --add not specified
- Add nickname field to AccountInfo (auto-generated from email prefix)
- Add generateNickname() and validateNickname() utility functions
- Update triggerOAuth() to accept add option
- Update registerAccountFromToken() to pass nickname
- Update help text with --add flag documentation

src/cliproxy/account-manager.ts

@@ -19,6 +19,8 @@ export interface AccountInfo {
   id: string;
   /** Email address from OAuth (if available) */
   email?: string;
+  /** User-friendly nickname for quick reference (auto-generated from email prefix) */
+  nickname?: string;
   /** Provider this account belongs to */
   provider: CLIProxyProvider;
   /** Whether this is the default account for the provider */
@@ -53,6 +55,36 @@ const DEFAULT_REGISTRY: AccountsRegistry = {
   providers: {},
 };
 
+/**
+ * Generate nickname from email
+ * Takes prefix before @ symbol, sanitizes whitespace
+ * Validation: 1-50 chars, any non-whitespace (permissive per user preference)
+ */
+export function generateNickname(email?: string): string {
+  if (!email) return 'default';
+  const prefix = email.split('@')[0];
+  // Sanitize: remove whitespace, limit to 50 chars
+  return prefix.replace(/\s+/g, '').slice(0, 50) || 'default';
+}
+
+/**
+ * Validate nickname
+ * Rules: 1-50 chars, any non-whitespace allowed (permissive)
+ * @returns null if valid, error message if invalid
+ */
+export function validateNickname(nickname: string): string | null {
+  if (!nickname || nickname.length === 0) {
+    return 'Nickname is required';
+  }
+  if (nickname.length > 50) {
+    return 'Nickname must be 50 characters or less';
+  }
+  if (/\s/.test(nickname)) {
+    return 'Nickname cannot contain whitespace';
+  }
+  return null;
+}
+
 /**
  * Get path to accounts registry file
  */
@@ -140,7 +172,8 @@ export function getAccount(provider: CLIProxyProvider, accountId: string): Accou
 export function registerAccount(
   provider: CLIProxyProvider,
   tokenFile: string,
-  email?: string
+  email?: string,
+  nickname?: string
 ): AccountInfo {
   const registry = loadAccountsRegistry();
 
@@ -161,9 +194,13 @@ export function registerAccount(
   const accountId = email || 'default';
   const isFirstAccount = Object.keys(providerAccounts.accounts).length === 0;
 
+  // Generate nickname if not provided
+  const accountNickname = nickname || generateNickname(email);
+
   // Create or update account
   providerAccounts.accounts[accountId] = {
     email,
+    nickname: accountNickname,
     tokenFile,
     createdAt: new Date().toISOString(),
     lastUsedAt: new Date().toISOString(),
@@ -181,6 +218,7 @@ export function registerAccount(
     provider,
     isDefault: accountId === providerAccounts.default,
     email,
+    nickname: accountNickname,
     tokenFile,
     createdAt: providerAccounts.accounts[accountId].createdAt,
     lastUsedAt: providerAccounts.accounts[accountId].lastUsedAt,
@@ -333,9 +371,10 @@ export function discoverExistingAccounts(): void {
       // Get file stats for creation time
       const stats = fs.statSync(filePath);
 
-      // Register account
+      // Register account with auto-generated nickname
       providerAccounts.accounts[accountId] = {
         email,
+        nickname: generateNickname(email),
         tokenFile: file,
         createdAt: stats.birthtime?.toISOString() || new Date().toISOString(),
         lastUsedAt: stats.mtime?.toISOString(),

src/cliproxy/auth-handler.ts

@@ -22,6 +22,7 @@ import { CLIProxyProvider } from './types';
 import {
   AccountInfo,
   discoverExistingAccounts,
+  generateNickname,
   getDefaultAccount,
   getProviderAccounts,
   registerAccount,
@@ -429,14 +430,15 @@ export function clearAuth(provider: CLIProxyProvider): boolean {
  * Auto-detects headless environment and uses --no-browser flag accordingly
  * @param provider - The CLIProxy provider to authenticate
  * @param options - OAuth options
+ * @param options.add - If true, skip confirm prompt when adding another account
  * @returns Account info if successful, null otherwise
  */
 export async function triggerOAuth(
   provider: CLIProxyProvider,
-  options: { verbose?: boolean; headless?: boolean; account?: string } = {}
+  options: { verbose?: boolean; headless?: boolean; account?: string; add?: boolean } = {}
 ): Promise<AccountInfo | null> {
   const oauthConfig = getOAuthConfig(provider);
-  const { verbose = false } = options;
+  const { verbose = false, add = false } = options;
 
   // Auto-detect headless if not explicitly set
   const headless = options.headless ?? isHeadlessEnvironment();
@@ -447,6 +449,34 @@ export async function triggerOAuth(
     }
   };
 
+  // Check for existing accounts and prompt if --add not specified
+  const existingAccounts = getProviderAccounts(provider);
+  if (existingAccounts.length > 0 && !add) {
+    console.log('');
+    console.log(
+      `[i] ${existingAccounts.length} account(s) already authenticated for ${oauthConfig.displayName}`
+    );
+
+    // Import readline for confirm prompt
+    const readline = await import('readline');
+    const rl = readline.createInterface({
+      input: process.stdin,
+      output: process.stdout,
+    });
+
+    const confirmed = await new Promise<boolean>((resolve) => {
+      rl.question('[?] Add another account? (y/N): ', (answer) => {
+        rl.close();
+        resolve(answer.toLowerCase() === 'y' || answer.toLowerCase() === 'yes');
+      });
+    });
+
+    if (!confirmed) {
+      console.log('[i] Cancelled');
+      return null;
+    }
+  }
+
   // Pre-flight check: verify OAuth callback port is available
   const preflight = await preflightOAuthCheck(provider);
   if (!preflight.ready) {
@@ -662,8 +692,8 @@ function registerAccountFromToken(
     const data = JSON.parse(content);
     const email = data.email || undefined;
 
-    // Register the account
-    return registerAccount(provider, newestFile, email);
+    // Register the account with auto-generated nickname
+    return registerAccount(provider, newestFile, email, generateNickname(email));
   } catch {
     return null;
   }

src/cliproxy/cliproxy-executor.ts

@@ -123,6 +123,7 @@ export async function execClaudeWithCLIProxy(
   const forceHeadless = args.includes('--headless');
   const forceLogout = args.includes('--logout');
   const forceConfig = args.includes('--config');
+  const addAccount = args.includes('--add');
 
   // Handle --config: configure model selection and exit
   // Pass customSettingsPath for CLIProxy variants to save to correct file
@@ -151,6 +152,7 @@ export async function execClaudeWithCLIProxy(
       const { triggerOAuth } = await import('./auth-handler');
       const authSuccess = await triggerOAuth(provider, {
         verbose,
+        add: addAccount,
         ...(forceHeadless ? { headless: true } : {}),
       });
       if (!authSuccess) {
@@ -260,7 +262,7 @@ export async function execClaudeWithCLIProxy(
   log(`Claude env: ANTHROPIC_MODEL=${envVars.ANTHROPIC_MODEL}`);
 
   // Filter out CCS-specific flags before passing to Claude CLI
-  const ccsFlags = ['--auth', '--headless', '--logout', '--config'];
+  const ccsFlags = ['--auth', '--headless', '--logout', '--config', '--add'];
   const claudeArgs = args.filter((arg) => !ccsFlags.includes(arg));
 
   const isWindows = process.platform === 'win32';

src/commands/help-command.ts

@@ -161,6 +161,7 @@ Claude Code Profile & Model Switcher`.trim();
       ['ccs qwen', 'Qwen Code (qwen3-coder)'],
       ['', ''], // Spacer
       ['ccs <provider> --auth', 'Authenticate only'],
+      ['ccs <provider> --auth --add', 'Add another account'],
       ['ccs <provider> --config', 'Change model (agy, gemini)'],
       ['ccs <provider> --logout', 'Clear authentication'],
       ['ccs <provider> --headless', 'Headless auth (for SSH)'],