feat: detect and persist Telegram Premium status after authentication

After TDLib login completes, calls getMe() to detect isPremium, persists
it to DB via updateAccountPremiumStatus, and returns { client, isPremium }
from createTdlibClient. All callers updated to destructure accordingly.

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

worker/src/rebuild.ts

@@ -63,7 +63,7 @@ export async function rebuildPackageDatabase(
     }
 
     const account = accounts[0];
-    const client = await createTdlibClient({
+    const { client } = await createTdlibClient({
       id: account.id,
       phone: account.phone,
     });