Refactor bot handlers and keyboards; implement admin features

- Removed unused prehandling, referrals, support, and states files.
- Updated admin and client handlers to improve structure and functionality.
- Introduced admin filters and routers for better access control.
- Added new billing and deposit functionalities for client interactions.
- Enhanced keyboard layouts for admin and client menus.
- Implemented promotion handling for admin users.
- Updated configuration to include admin settings.
- Improved utility functions for quote fetching and menu text building.
- Added common handlers for undefined commands and message deletions.

bot/handlers/client/referals.py

@@ -0,0 +1,28 @@
+from aiogram import F, Router
+from aiogram.fsm.context import FSMContext
+from aiogram.types import CallbackQuery
+from aiogram.utils.deep_linking import create_start_link
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from bot.keyboards.client import referals_kb
+from bot.texts import REFERALS_MENU
+from misc.utils import format_share_deep_link
+from schemas.di import DependenciesDTO
+
+router = Router()
+
+
+@router.callback_query(F.data == "referal")
+async def referal_menu(
+    cb: CallbackQuery, state: FSMContext, session: AsyncSession, deps: DependenciesDTO
+):
+    await state.clear()
+
+    user = await deps.user_repository.get_user_by_id(session, cb.from_user.id)
+    referal_link = await create_start_link(cb.bot, f"ref_{user.id}", encode=True)
+    share_link = format_share_deep_link(referal_link)
+
+    await cb.message.edit_text(
+        REFERALS_MENU.format(balance=user.balance, link=referal_link),
+        reply_markup=referals_kb(share_link),
+    )