Restore upstream attribution in NOTICE (Qwen3-Embedding-8B)

NOTICE

@@ -1,5 +1,8 @@
-Zen
+zen-embedding
 Copyright 2025-2026 Zen Authors
 
-This model and its accompanying code are licensed under the Apache License, Version 2.0.
-Zen models are developed by the Zen Authors (https://zenlm.org).
+This model is a derivative work distributed under the Apache-2.0 license.
+A copy of the license is in the accompanying LICENSE file.
+
+Built on:
+- Qwen3-Embedding-8B (https://huggingface.co/Qwen/Qwen3-Embedding-8B), Apache-2.0.