fix(release): use bare_version for prerelease flag (tray- prefix has a dash)

[ntatschner]

Summary

Every tray release since the release-tracks split (PR #91) was silently flagged as isPrerelease: true on GitHub's Releases page — including bare-semver live releases. The "Latest" badge stayed on the pre-split v1.8.3 until I manually corrected tray-v1.8.6 outside this PR.

Root cause

release.yml line 380:

prerelease: ${{ contains(github.ref_name, '-') }}

This was designed for the pre-split vX.Y.Z[-channel.N] tag schema, where only pre-releases contained a hyphen. After PR #91 changed the tag schema to tray-vX.Y.Z[-channel.N], the tray- prefix itself contains a hyphen — so contains(...) returned true for every tray release including bare-semver live ones.

CI green throughout (the flag is a property of the published release, not a build error), so the bug never tripped any automated check.

Fix

Use needs.validate-tag.outputs.bare_version — validate-tag already strips both tray- and the leading v for the manifest generator, and exposes the result as an output. The bare version is 1.8.6 for live (no hyphen → not prerelease) and 1.8.6-rc.1 for rc (hyphen → prerelease). One-line check, same semantics as the original intent.

Already corrected outside this PR

gh release edit tray-v1.8.6 --prerelease=false --latest=true
gh release edit tray-v1.8.5 --prerelease=false

So your public Releases page now shows tray-v1.8.6 as Latest. The intervening pre-release tags stay flagged correctly. Verified via gh api repos/.../releases/latest.

Test plan

• release.yml YAML parses cleanly
• Next tray pre-release tag (e.g. tray-v1.8.7-alpha.1 from auto-alpha after merge) publishes with isPrerelease: true — correct
• Next tray live tag (e.g. tray-v1.8.7) publishes with isPrerelease: false AND becomes the new "Latest" — correct