ci: Add FLUX/diffusion support to scripts/performance/run_recipe.py (#3176)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: suiyoubi

src/megatron/bridge/recipes/flux/__init__.py

@@ -0,0 +1,15 @@
+# Copyright (c) 2025, NVIDIA CORPORATION.  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 megatron.bridge.diffusion.recipes.flux import *  # noqa: F401, F403