Related tasks for Alpine (musl) x64 promotion to Tier 2

Current status

Platform list currently contains the following entry:

Other architectures are unlisted, and have no designated support type.

Official binary platforms and toolchains does not list any Alpine / musl build.

node Docker images for Alpine are built from https://unofficial-builds.nodejs.org/download/release/v<node-version>/node-v<node-version>-linux-x64-musl.tar.xz

• Alpine x64 images are built using the x64-musl build directly
• Alpine arm64, arm32 and s390x images are built from source

Update automation treats security releases differently and proceeds with these releases without waiting for musl build availability.

Proposed Node.js change

PR https://github.com/nodejs/node/pull/63737 proposes the promotion of Alpine/x64 to Tier 2.

This can be expected to add Alpine/x64 to the Platform list and to Official binary platforms and toolchains.

An x64-musl build can be expected to be available through the regular https://nodejs.org/download/release/ website.

Impact

Expected update tasks and impact will include:

• Documentation README references to support category and process
• Dockerfile-alpine.template to source the musl build from https://nodejs.org/download/release/
• update.sh script so that the -s (security) option does not exclude Alpine builds, or for more simplification, remove the -s option entirely, since it becomes a no-op
• build-automation.mjs remove checks against https://unofficial-builds.nodejs.org

Review other Alpine-related issues and PR for relevance and applicability.

先从 README、Dockerfile-alpine.template、update.sh 和 build-automation.mjs 开始，然后审查链接的 Node.js 晋级事项和其他 Alpine issue。更新文档中的支持流程，为 Alpine x64 使用常规的 Node.js 发布源，并在 Tier 2 晋级到位后移除已过时的 unofficial-builds 检查和安全发布处理。