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`.

bot/handlers/__init__.py

@@ -0,0 +1,19 @@
+from .ads import router as ads_router
+from .billing import router as billing_router
+from .buy import router as buy_router
+from .common import router as common_router
+from .menus import router as menus_router
+from .prehandling import router as prehandling_router
+from .referals import router as referal_router
+from .support import router as support_router
+
+routers = [
+    prehandling_router,
+    referal_router,
+    billing_router,
+    menus_router,
+    ads_router,
+    support_router,
+    buy_router,
+    common_router,
+]