feat: Implement payment notification system and API structure

- Added notifications for successful payments in `api/core/notifications.py`.
- Created main API entry point in `api/main.py` with FastAPI integration.
- Established routing structure in `api/routes/__init__.py` and `api/routes/pally.py` for handling payment callbacks.
- Developed billing handlers in `bot/handlers/billing.py` and `bot/handlers/buy.py` for subscription management.
- Introduced state management for user interactions in `bot/states/`.
- Created user interface elements in `bot/keyboards/` for navigation and payment processing.
- Set up middleware for dependency injection in `bot/middlewares/di.py`.
- Added support for user commands and interactions in `bot/handlers/common.py` and `bot/handlers/support.py`.
- Implemented logging and error handling throughout the bot's functionality.
- Created entry point script for API server in `entrypoints/api.sh`.

api/core/deps.py

@@ -0,0 +1,18 @@
+from aiogram import Bot
+from fastapi import Request
+
+from db.session import async_session
+from schemas.di import APIDependenciesDTO
+
+
+def get_bot(request: Request) -> Bot:
+    return request.app.state.bot
+
+
+async def get_db():
+    async with async_session() as db:
+        yield db
+
+
+def get_deps(request: Request) -> APIDependenciesDTO:
+    return request.app.state.deps

api/core/notifications.py

@@ -0,0 +1,13 @@
+from aiogram import Bot
+from aiogram.types import InlineKeyboardButton, InlineKeyboardMarkup
+from aiogram.utils.keyboard import InlineKeyboardBuilder
+
+SUCCESSFUL_PAYMENT = "<b>💸 Зачислен платёж на {amount}₽</b>"
+
+close_kb: InlineKeyboardMarkup = InlineKeyboardBuilder(
+    [[InlineKeyboardButton(text="❌", callback_data="delete")]]
+).as_markup()
+
+
+async def successful_payment_notification(bot: Bot, user_id: int, amount: int):
+    await bot.send_message(user_id, SUCCESSFUL_PAYMENT.format(amount=amount), reply_markup=close_kb)