Expose sarm package API and ship reward model card template (#3477)

* chore: List lerobot_rewardmodel_modelcard_template.md in MANIFEST.in

* chore: export SARMConfig, SARMRewardModel, and make_sarm_pre_post_processors from rewards.sarm.

MANIFEST.in

@@ -1,3 +1,4 @@
 include src/lerobot/templates/lerobot_modelcard_template.md
+include src/lerobot/templates/lerobot_rewardmodel_modelcard_template.md
 include src/lerobot/datasets/card_template.md
 include src/lerobot/envs/metaworld_config.json

src/lerobot/rewards/sarm/__init__.py

@@ -0,0 +1,19 @@
+# Copyright 2026 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .configuration_sarm import SARMConfig
+from .modeling_sarm import SARMRewardModel
+from .processor_sarm import make_sarm_pre_post_processors
+
+__all__ = ["SARMConfig", "SARMRewardModel", "make_sarm_pre_post_processors"]