Refactor bot initialization and routing logic to enforce webhook mode requirement

- Updated the bot's startup logic to require a configured WEBHOOK_BASE_URL, exiting if not set, and logging appropriate error messages.
- Simplified the decision-making process for running the AIOHTTP server, ensuring it only runs in webhook mode.
- Enhanced the router configuration to filter updates for private chats, improving message handling security.

bot/routers.py

@@ -1,4 +1,4 @@
-from aiogram import Router
+from aiogram import Router, F
 
 from bot.handlers.user import user_router_aggregate
 from bot.handlers import inline_mode
@@ -10,6 +10,10 @@ from config.settings import Settings
 def build_root_router(settings: Settings) -> Router:
     root = Router(name="root")
 
+    # Allow all updates only in private chats (messages, callback queries, etc.)
+    root.message.filter(F.chat.type == "private")
+    root.callback_query.filter(F.message.chat.type == "private")
+
     # Public routers
     root.include_router(user_router_aggregate)
     root.include_router(inline_mode.router)