Add CHANGELOG.md entry for Gangs coordinator rank fix

Author: joaopedroassad

CHANGELOG.md

@@ -7,6 +7,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Gemma 4 model family (E4B, 31B, 26B-A4B) with base and instruction-tuned variants. Includes decoder with Per-Layer Embeddings (PLE), partial RoPE, KV sharing across sliding/global attention layers, Mixture-of-Experts (26B-A4B), QK/V-norm, logit soft-capping, audio tower (Conformer encoder for multimodal E4B), bidirectional HuggingFace state dict conversion, FSDP/activation checkpointing/tensor parallel support, and SFT recipe configs.
 - Bump transformers~=v5.5 and loosen huggingface_hub upper bound. (#1508)
 - Fixed typo in WerMetric: use `hyp_seqs` instead of `ref_seqs` for `hyp_seqs_list`. (#1506)
+- Fixed operator precedence in the `Gangs` coordinator rank check so that a `root.rank == 0` process that is not rank 0 in any single parallel gang (data, tensor, or pipeline) is correctly rejected.
 
 ## [0.8.0] - March 25th, 2026
 - fsspec integration for remote filesystem support. Checkpoints can be saved to and loaded from S3 via `--checkpoint-dir s3://bucket/path/`. Requires `s3fs`. (#1126)