deploy: b300 build scripts with pip cache mount + no-build-isolation fast path

Base image already has torch 2.13, but pyproject build-system.requires
pulls it into pip's isolated build env on every build (~6GB via throttled
mirror, 47min). --no-build-isolation reuses the base env; build.sh picks
Dockerfile.fast (--no-deps) when python/pyproject.toml is unchanged.

deploy/b300-build/build.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# 用法: /data/ymk/build/build.sh [tag]
+# 默认 tag: ymkymx/sglang:<分支>-<sha9>-local-<UTC构建日期时间>（命名规则见 AGENTS.md）
+# 另打 <分支>-latest-local 别名。
+#
+# 依赖路径自动选择：
+#   python/pyproject.toml 的 sha256 与上次成功构建一致 → Dockerfile.fast（--no-deps，秒级）
+#   不一致（或 FULL=1）→ Dockerfile 全量依赖解析，成功后记录新 hash
+set -euo pipefail
+cd /data/ymk
+SHA=$(git -C sglang rev-parse --short=9 HEAD)
+BR=$(git -C sglang rev-parse --abbrev-ref HEAD)
+DT=$(date -u +%Y%m%d-%H%M)
+TAG=${1:-ymkymx/sglang:$BR-$SHA-local-$DT}
+
+HASH_FILE=build/.last_pyproject_sha256
+CUR=$(sha256sum sglang/python/pyproject.toml | cut -d' ' -f1)
+PREV=$(cat "$HASH_FILE" 2>/dev/null || echo none)
+
+DOCKERFILE=build/Dockerfile
+if [ "$CUR" = "$PREV" ] && [ "${FULL:-0}" != "1" ]; then
+  DOCKERFILE=build/Dockerfile.fast
+  echo "== pyproject 未变，走 fast 路径（--no-deps）"
+else
+  echo "== pyproject 有变化或 FULL=1，走全量依赖解析"
+fi
+
+echo "== building $TAG from sglang@$(git -C sglang log --oneline -1) [$DOCKERFILE]"
+docker build -f "$DOCKERFILE" -t "$TAG" .
+# 构建成功才记录 hash / 打别名
+echo "$CUR" > "$HASH_FILE"
+docker tag "$TAG" "ymkymx/sglang:$BR-latest-local"
+echo "== done: $TAG （别名 $BR-latest-local）"