🚚 Refactor and simplify backend file structure (#609)

src/backend/app/schemas/token.py

@@ -0,0 +1,12 @@
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class Token(BaseModel):
+    access_token: str
+    token_type: str
+
+
+class TokenPayload(BaseModel):
+    sub: Optional[int] = None