The release workflow was still publishing a hard-coded GitHub Release body,
which forced manual copy-paste of each version's markdown after the build
finished. This change makes tagged releases load release-notes/vX.Y.Z.md
from the tagged commit and fail fast when the file or version/tag alignment
is missing. The local release script now enforces the same contract and
stages the matching markdown file into the release commit automatically.
Constraint: GitHub Releases must be generated from the tagged commit so the workflow can only read files already present at that revision
Rejected: Keep a hard-coded releaseBody in workflow | still requires manual release-page editing every version
Rejected: Store release notes only outside git state | workflow cannot read local-only markdown during tag-triggered builds
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Keep release-notes/vX.Y.Z.md as the canonical source for GitHub Release bodies and preserve the tag/version validation gate
Tested: ruby -e 'require "yaml"; YAML.load_file(".github/workflows/release-desktop.yml"); puts "YAML OK"'
Tested: bun run scripts/release.ts 0.1.5 --dry
Tested: git diff --check
Not-tested: End-to-end GitHub Actions release run against a pushed tag
