skills: update buildspace skills for v1.8.0

[photon-action-bot]

Skills Update: buildspace v1.8.0

This PR updates skills documentation for buildspace based on the v1.8.0 release.

Release Notes

New Features

• Added support for extra artifacts during the release process, so release outputs can include more than the main build artifact. ✨

Bug Fixes

• publish-npm now fails directly when npm publish steps error, making release failures easier to catch.
• publish-npm now verifies that the published version actually lands on the npm registry, which helps catch silent publish failures.

Improvement

• Removed extra-artifact handling from the build process, keeping artifact support focused on releases where it belongs.

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🤖 This PR was auto-generated by Claude Code via the update-skills action in buildspace.

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