docs: add NOTICE attribution file per Apache-2.0 s4(b)

NOTICE

@@ -0,0 +1,52 @@
+Mask2Former Swin-Tiny (COCO Instance) weights — acaua mirror
+============================================================
+
+This product includes model weights developed by the following parties:
+
+ - Meta AI Research / FAIR (Mask2Former authors)
+   Reference implementation and released weights.
+   https://github.com/facebookresearch/Mask2Former
+   Cheng et al., "Masked-attention Mask Transformer for Universal
+   Image Segmentation", CVPR 2022, arXiv:2112.01527.
+
+ - Swin Transformer authors
+   Liu et al., "Swin Transformer: Hierarchical Vision Transformer
+   using Shifted Windows", ICCV 2021, arXiv:2103.14030.
+
+ - Hugging Face (integration into 🤗 Transformers, weight conversion,
+   model card on facebook/mask2former-swin-tiny-coco-instance)
+   https://huggingface.co/facebook/mask2former-swin-tiny-coco-instance
+
+License notes
+-------------
+The reference implementation at facebookresearch/Mask2Former is released
+under the MIT License. The pretrained weights redistributed here (as hosted
+upstream on facebook/mask2former-swin-tiny-coco-instance) are declared
+Apache-2.0 in the upstream model card YAML. This mirror preserves that
+declaration.
+
+Attribution chain
+-----------------
+Mirrored on 2026-04-17 by CondadosAI from:
+
+    repo:   facebook/mask2former-swin-tiny-coco-instance
+    commit: 22c4a2f15dc88149b8b8d9f4d42c54431fbd66f6
+    date:   2023-09-11
+
+No weights or configuration have been modified. This mirror exists to pin
+a specific revision for reproducible, audit-clean use by the acaua library
+(https://github.com/CondadosAI/acaua).
+
+License
+-------
+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.