ci : add nightly-tag.txt to make-release (#27485)

As agreed in ggml discussion #1579, the official semver releases now
include a nightly-tag.txt asset containing the tag of the corresponding
nightly release (e.g. b10485). The Web UI assets are published to the
HF bucket under the nightly tag, so this makes them discoverable for
each official release.

- make-release-desc.sh: expose the resolved nightly tag as a
  nightly_tag output
- make-release.yml: create nightly-tag.txt from that tag, upload it
  as a release asset (skipped on dry-run), mention it in the release
  body and in the dry-run summary

Assisted-by: pi:llama.cpp/Qwen3.8-27B

.github/workflows/make-release.yml

@@ -55,6 +55,20 @@ jobs:
         env:
           GITHUB_REPOSITORY: ${{ github.repository }}
 
+      - name: Create nightly-tag.txt
+        id: nightly_tag_file
+        run: |
+          NIGHTLY_TAG="${{ steps.desc.outputs.nightly_tag }}"
+          if [[ -z "${NIGHTLY_TAG}" ]]; then
+            echo "Warning: no nightly tag found for the release commit - nightly-tag.txt will not be created"
+            echo "create=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          echo "${NIGHTLY_TAG}" > nightly-tag.txt
+          echo "create=true" >> "$GITHUB_OUTPUT"
+          echo "nightly-tag.txt:"
+          cat nightly-tag.txt
+
       - name: Create release
         if: ${{ github.event.inputs.dry_run == 'false' }}
         uses: ggml-org/action-create-release@v1
@@ -70,18 +84,41 @@ jobs:
             New version has been released.
 
             ${{ steps.desc.outputs.nightly }}
+
+            **Web UI:** the `nightly-tag.txt` asset contains the tag of the corresponding nightly release
+
             **More info:** [dist : releases and versioning of ggml-org projects](https://github.com/ggml-org/ggml/discussions/1579)
 
             ## ${{ steps.desc.outputs.changelog_title }}
 
             ${{ steps.desc.outputs.changelog }}
 
+      - name: Upload nightly-tag.txt
+        if: ${{ github.event.inputs.dry_run == 'false' && steps.nightly_tag_file.outputs.create == 'true' }}
+        uses: actions/github-script@v8
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          script: |
+            const fs = require('fs');
+            const release_id = '${{ steps.create_release.outputs.id }}';
+            console.log('uploadReleaseAsset', 'nightly-tag.txt');
+            await github.rest.repos.uploadReleaseAsset({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              release_id: release_id,
+              name: 'nightly-tag.txt',
+              data: await fs.readFileSync('./nightly-tag.txt')
+            });
+
       - name: Dry run summary
         if: ${{ github.event.inputs.dry_run == 'true' }}
         run: |
           if [[ "${{ steps.checks.outputs.checks_passed }}" == "true" ]]; then
             echo "Dry run complete - all checks passed."
             echo "Would have created tag: ${{ steps.checks.outputs.version }}"
+            if [[ -n "${{ steps.desc.outputs.nightly_tag }}" ]]; then
+              echo "Would have uploaded nightly-tag.txt: ${{ steps.desc.outputs.nightly_tag }}"
+            fi
           else
             echo "::error::Dry run found release check failures. A release tag would not be created."
             exit 1

scripts/make-release-desc.sh

@@ -15,7 +15,8 @@
 # tag exists.
 #
 # Env (when running in GitHub Actions):
-#   GITHUB_OUTPUT: previous_tag, changelog_title, changelog and nightly are written here
+#   GITHUB_OUTPUT: previous_tag, changelog_title, changelog, nightly and nightly_tag
+#     are written here
 #   GITHUB_REPOSITORY: owner/repo, used to build the nightly release URL (skipped when unset)
 set -euo pipefail
 
@@ -80,6 +81,7 @@ if [[ -n "${GITHUB_OUTPUT:-}" ]]; then
         echo "previous_tag=${PREV}"
         echo "changelog_title=${CHANGELOG_TITLE}"
         echo "nightly=${NIGHTLY}"
+        echo "nightly_tag=${NIGHTLY_TAG}"
         echo "changelog<<CHANGELOG_EOF"
         echo "${CHANGELOG}"
         echo "CHANGELOG_EOF"