fix(build): patch_ops.sh加cd "$(dirname "$0")" + VLLM_ROOT fallback搜索

26e6cb40能build是因为patch_ops.sh第14行有cd "$(dirname "$0")"
HEAD版本删了这行, 导致from patch_utils import失败(CWD不对),
set -uo pipefail下VLLM_ROOT未定义, 脚本exit 2, Docker build失败。

修复:
1. patch_ops.sh顶部加回 cd "$(dirname "$0")"
2. Python heredoc加 || true
3. 加fallback VLLM_ROOT手动搜索(3个常见路径)
4. Dockerfile用cd && bash确保双保险

qwen3_6_scripts/patch_ops.sh

@@ -33,6 +33,10 @@
 # (xformers, diagnostics) may legitimately fail if the base image differs.
 set -uo pipefail
 
+# Always cd to script directory so relative paths (./qwen3_5.py, ./vendor_overrides, etc) work
+cd "$(dirname "$0")"
+build_stage "patch_ops.sh running from $(pwd)"
+
 build_stage() { printf '[BI100 BUILD] %s\n' "$1" >&2; }
 require_file() {
     local path=$1