fix: address CodeRabbit review feedback from PR #122

- release-engine.yml: add docker/setup-qemu-action@v3 before Buildx
  to support multi-platform (ARM64) Docker builds; without QEMU,
  ARM64 RUN layers fail in buildx emulation
- RELEASING.md: replace [the relevant issue] placeholder with actual
  link to #123 (rename release-please.yml to changeset-version.yml)

https://claude.ai/code/session_01CuTGMFzUAdw5L5p5n9vEa5

Author: claude

.github/workflows/release-engine.yml

@@ -29,6 +29,8 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - uses: docker/setup-qemu-action@v3
+
       - uses: docker/setup-buildx-action@v3
 
       - name: Set goreleaser tag

RELEASING.md

@@ -28,7 +28,7 @@ The automated CI path (Version PR → merge) requires no local tooling beyond gi
 5b. release-helm.yml    → helm push OCI + GitHub Release
 ```
 
-> **Note on workflow naming:** `release-please.yml` is named after a tool we evaluated but didn't adopt — it actually runs the Changesets CLI. A rename to `changeset-version.yml` is tracked in [the relevant issue].
+> **Note on workflow naming:** `release-please.yml` is named after a tool we evaluated but didn't adopt — it actually runs the Changesets CLI. A rename to `changeset-version.yml` is tracked in [dvflw/mantle#123](https://github.com/dvflw/mantle/issues/123).
 
 ## Step 1: Add a Changeset (During Development)