Build from SGLang main for Qwen3.5/GLM-5 PD disagg fixes

v0.5.10 is missing merged PRs #19002, #19076, #19086 that fix
non-MLA PD disaggregation (GQA head count, KV cache slice transfer,
mamba cache size). Building from main includes all these fixes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: JordanNanos

docker/build-sglang-bnxt-mi325x.sh

@@ -28,9 +28,9 @@
 set -euo pipefail
 
 # ---------- Configuration ----------
-SGL_BRANCH="${SGL_BRANCH:-v0.5.10}"
+SGL_BRANCH="${SGL_BRANCH:-main}"
 GPU_ARCH="gfx942"
-IMAGE_TAG="${IMAGE_TAG:-semianalysiswork/sgl-bnxt-cdna3:v0.5.10-bnxt}"
+IMAGE_TAG="${IMAGE_TAG:-semianalysiswork/sgl-bnxt-cdna3:main-bnxt}"
 DOCKERFILE_REPO="https://github.com/JordanNanos/sglang.git"
 DOCKERFILE_REF="main"