feat: Lensa bot stub — MessengerService interface ready for SDK integration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/messengers/lensa/bot.py

@@ -0,0 +1,44 @@
+import logging
+
+from fastapi import Request, Response
+
+from app.messengers.base import MessengerService
+
+logger = logging.getLogger(__name__)
+
+
+class LensaService(MessengerService):
+    """
+    Stub implementation for Lensa (IVA Technologies) messenger bot.
+
+    Lensa's Bot API/SDK is not publicly available.
+    This stub provides the MessengerService interface so the integration
+    can be implemented when SDK access is obtained from IVA Technologies.
+
+    To integrate:
+    1. Obtain SDK/API documentation from IVA Technologies (iva-tech.ru)
+    2. Implement the abstract methods below
+    3. Register webhook endpoint in main.py (similar to Telegram)
+    """
+
+    async def setup(self):
+        logger.info("Lensa bot: stub — SDK not available, skipping setup")
+
+    async def shutdown(self):
+        logger.info("Lensa bot: stub — shutting down")
+
+    async def send_message(self, chat_id: str, text: str, **kwargs):
+        logger.warning(f"Lensa bot: send_message not implemented (chat_id={chat_id})")
+
+    async def send_file(self, chat_id: str, file_path: str, caption: str = ""):
+        logger.warning(f"Lensa bot: send_file not implemented (chat_id={chat_id})")
+
+    async def notify_progress(self, chat_id: str, status: str, progress: int | None = None):
+        logger.warning(f"Lensa bot: notify_progress not implemented (chat_id={chat_id})")
+
+    async def feed_webhook(self, request: Request) -> Response:
+        logger.warning("Lensa bot: webhook received but SDK not implemented")
+        return Response(status_code=200)
+
+
+lensa_service = LensaService()