docs: add docs to CB

Pretty much every class and method should have documentation now.

ref: N25B-295

src/control_backend/api/v1/endpoints/program.py

@@ -11,8 +11,14 @@ router = APIRouter()
 @router.post("/program", status_code=202)
 async def receive_message(program: Program, request: Request):
     """
-    Receives a BehaviorProgram, pydantic checks it.
-    Converts it into real Phase objects.
+    Endpoint to upload a new Behavior Program.
+
+    Validates the program structure (phases, norms, goals) and publishes it to the internal
+    'program' topic. The :class:`~control_backend.agents.bdi.bdi_program_manager.BDIProgramManager`
+    will pick this up and update the BDI agent.
+
+    :param program: The parsed Program object.
+    :param request: The FastAPI request object.
     """
     logger.debug("Received raw program: %s", program)