feat(mosaic): gateway token recovery via BetterAuth cookie (#411)

packages/mosaic/src/commands/gateway/login.ts

@@ -0,0 +1,39 @@
+import { createInterface } from 'node:readline';
+import { signIn, saveSession } from '../../auth.js';
+import { readMeta } from './daemon.js';
+
+/**
+ * Shared login helper used by both `mosaic login` and `mosaic gateway login`.
+ * Prompts for email/password if not supplied, signs in, and persists the session.
+ */
+export async function runLogin(opts: {
+  gatewayUrl: string;
+  email?: string;
+  password?: string;
+}): Promise<void> {
+  let email = opts.email;
+  let password = opts.password;
+
+  if (!email || !password) {
+    const rl = createInterface({ input: process.stdin, output: process.stdout });
+    const ask = (q: string): Promise<string> => new Promise((resolve) => rl.question(q, resolve));
+
+    if (!email) email = await ask('Email: ');
+    if (!password) password = await ask('Password: ');
+    rl.close();
+  }
+
+  const auth = await signIn(opts.gatewayUrl, email, password);
+  saveSession(opts.gatewayUrl, auth);
+  console.log(`Signed in as ${auth.email} (${opts.gatewayUrl})`);
+}
+
+/**
+ * Derive the gateway base URL from meta.json with a fallback.
+ */
+export function getGatewayUrl(overrideUrl?: string): string {
+  if (overrideUrl) return overrideUrl;
+  const meta = readMeta();
+  if (meta) return `http://${meta.host}:${meta.port.toString()}`;
+  return 'http://localhost:14242';
+}