refactor: Improve code readability and structure across TTS modules

app/repositories/tts.py

@@ -1,7 +1,10 @@
 """TTS repository for database operations."""
 
 from collections.abc import Sequence
-from typing import Any
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from sqlalchemy.ext.asyncio import AsyncSession
 
 from sqlmodel import select
 
@@ -12,7 +15,13 @@ from app.repositories.base import BaseRepository
 class TTSRepository(BaseRepository[TTS]):
     """Repository for TTS operations."""
 
-    def __init__(self, session: Any) -> None:
+    def __init__(self, session: "AsyncSession") -> None:
+        """Initialize TTS repository.
+
+        Args:
+            session: Database session for operations
+
+        """
         super().__init__(TTS, session)
 
     async def get_by_user_id(