Prepare for v27 #1187

Pull requests needed to prepare the v27.x release line. The first Alpha, v27.0.0-alpha.0.0.0, is planned for 2026-10-28.

• nodejs/changelog-maker: fix: recognise alpha release commits (fix: recognise alpha release commits changelog-maker#279)
• nodejs/node-core-utils: feat(release): support alpha releases (feat(release): support alpha releases node-core-utils#1224)
• nodejs/nodejs-dist-indexer: feat: support alpha versions (feat: support alpha versions nodejs-dist-indexer#107)
• nodejs/node: build,doc,tools: support alpha releases (build,doc,tools: support alpha releases node#66796)
• nodejs/remark-preset-lint-node: feat: accept alpha versions in YAML comments (feat: accept alpha versions in YAML comments remark-preset-lint-node#729)
• nodejs/build: build: add expected assets for v27.x (build: add expected assets for v27.x build#4522)
• nodejs/nodejs.org: feat: support the Alpha release phase (feat: support the Alpha release phase nodejs.org#9223)
• nodejs/Release: doc: document the Alpha phase and v27 schedule (doc: document the Alpha phase and v27 schedule #1188)

These are all the changes I could map. If I missed something, please let me know in this issue.

cc @nodejs/releasers