All flows are now reachable from /menu (alias for /start). Single message
edits in place via editMessageText for hierarchical navigation, every leaf
has ⬅ Back / ⬅ Main Menu buttons.
Menu hierarchy:
/menu → main menu
📒 Accounts → list (each account is a button)
📒 <Account> → detail (📂 Groups | 🗑 Unpair | ⬅ back)
📂 Groups → groups list (⬅ back to account, ⬅ main menu)
🗑 Unpair → confirm (✅ yes | ⬅ cancel) → done
📡 Pair New → prompt for label, operator replies as plain message
❓ Help → help text + ⬅ Main Menu
Implementation notes:
- New menus.ts module with pure render functions for each view
- New state.ts tracks pending "awaiting pair label" per Telegram user
- bot.on("message:text") consumes the pending label after Pair New
- /pair, /unpair, /groups commands still work for power users; they reuse
the same handlers behind the scenes (executePairFlow extracted from
handlePair so the menu and the command share one path)