Align release automation with upstream workflow

[LunaStev]

Summary

• align Vex publication with Wave's manual release workflow
• create the authoritative upstream tag and GitHub Release together
• generate GitHub release notes from merged changes

Why

Official releases must originate from wavefnd/Vex:master, even when development happens through a fork. Tag creation should occur only after every target archive and checksum has passed validation.

Behavior

• the workflow accepts version, draft, and prerelease inputs
• validation rejects forks, non-master refs, stale commits, version mismatches, and existing tags
• all six target packages and the complete checksum set must succeed first
• the final release command targets the validated upstream commit, creates the tag, generates notes, and attaches all assets
• draft mode defaults on and prerelease mode defaults off

Validation

• python3 x.py check
• both workflows passed actionlint v1.7.12
• release workflow YAML parsed successfully
• git diff --check passed