ci: restore latest.json updates for prerelease tags (#4903)

PR #4582 gated the update-latest-version job to stable release tags so prereleases could not overwrite the stable version pointer. But the project currently ships prerelease tags only (beta previews), so the job never runs and latest.json has been stale since. Run the job for every release tag again, and keep the honest half of the #4582 fix by writing release_type from the actual build type instead of hardcoding "stable".

.github/workflows/build.yml

@@ -848,12 +848,14 @@ jobs:
 
           echo "✅ All assets uploaded successfully"
 
-  # Update latest.json for stable releases only: prerelease tags (alpha/beta/
+  # Update latest.json for every release tag (stable and prerelease): the
-  # rc) must never overwrite the stable version pointer.
+  # project currently ships prerelease tags only, so gating this to stable
+  # left the version pointer permanently stale. release_type records whether
+  # the pointed-to version is a prerelease.
   update-latest-version:
     name: Update Latest Version
     needs: [ build-check, upload-release-assets ]
-    if: startsWith(github.ref, 'refs/tags/') && needs.build-check.outputs.build_type == 'release'
+    if: startsWith(github.ref, 'refs/tags/')
     runs-on: ubuntu-latest
     steps:
       - name: Update latest.json
@@ -872,6 +874,12 @@ jobs:
           VERSION="${{ needs.build-check.outputs.version }}"
           TAG="${{ needs.build-check.outputs.version }}"
 
+          if [[ "${{ needs.build-check.outputs.build_type }}" == "prerelease" ]]; then
+            RELEASE_TYPE="prerelease"
+          else
+            RELEASE_TYPE="stable"
+          fi
+
           # Install ossutil
           OSSUTIL_VERSION="2.1.1"
           OSSUTIL_ZIP="ossutil-${OSSUTIL_VERSION}-linux-amd64.zip"
@@ -892,7 +900,7 @@ jobs:
             "version": "${VERSION}",
             "tag": "${TAG}",
             "release_date": "$(date -u +%Y-%m-%dT%H:%M:%SZ)",
-            "release_type": "stable",
+            "release_type": "${RELEASE_TYPE}",
             "download_url": "https://github.com/${{ github.repository }}/releases/tag/${TAG}"
           }
           EOF
@@ -900,7 +908,7 @@ jobs:
           # Upload to OSS
           "$OSSUTIL_BIN" cp latest.json oss://rustfs-version/latest.json --force
 
-          echo "✅ Updated latest.json for stable release $VERSION"
+          echo "✅ Updated latest.json for ${RELEASE_TYPE} release $VERSION"
 
   # Publish release (remove draft status)
   publish-release: