feat: admin-scoped Telegram menu

setMyCommands now runs at default scope (user commands only) plus once
per ADMIN_ID with scope:{type:'chat'} carrying the full set, so admin
commands (/addgroup, /delgroup, /listgroup) are hidden from non-admins'
menu. requireAdminUser remains the actual auth gate; this is UI cleanup.

parseAdminIds extracted to src/util/parse-admin-ids.js — shared between
config loading and the register script. ADMIN_IDS now required by
register-webhook.js (.env.deploy.example updated). Per-admin call uses
allowFail to gracefully skip admins who haven't DMed the bot yet.

.env.deploy.example

@@ -6,6 +6,10 @@
 TELEGRAM_BOT_TOKEN=
 TELEGRAM_WEBHOOK_SECRET=
 
+# Comma-separated Telegram user IDs (must match Vercel ADMIN_IDS).
+# register-webhook.js sets a chat-scoped menu (with admin commands) per ID.
+ADMIN_IDS=
+
 # Where Telegram should send webhook updates.
 # Format: https://<your-vercel-url>/api/webhook
 WORKER_URL=https://store-scraper-bot.vercel.app/api/webhook