Mirror releases and seed README in AlvinArch-releases for discovery

Create a matching git tag + release in alvinlollo/AlvinArch-releases next to
the main repo release, seed a short README there pointing back to
AlvinArch (workflow status badges on top), and extend release pruning to
the releases repo so both stay capped at 3.

.gitea/workflows/build-iso.yaml

@@ -162,9 +162,23 @@ jobs:
           for zst in "${zst_files[@]}"; do
             cp "$zst" "$REPO_DIR/releases/$TAG_NAME/"
           done
+
+          # Seed a short README redirecting to the main repo (status badges on top)
+          cat > "$REPO_DIR/README.md" <<'MDEOF'
+          [![Scheduled ArchISO Build](https://git.vilaythong.us/alvinlollo/AlvinArch/actions/workflows/build-iso.yaml/badge.svg?branch=main)](https://git.vilaythong.us/alvinlollo/AlvinArch/actions?workflow=build-iso.yaml)
+          [![Tests](https://git.vilaythong.us/alvinlollo/AlvinArch/actions/workflows/tests.yaml/badge.svg?branch=main)](https://git.vilaythong.us/alvinlollo/AlvinArch/actions?workflow=tests.yaml)
+
+          # AlvinArch Releases
+
+          Compressed (zstd) Arch Linux live ISOs built automatically by
+          [alvinlollo/AlvinArch](https://git.vilaythong.us/alvinlollo/AlvinArch).
+
+          **Main repository:** [alvinlollo/AlvinArch](https://git.vilaythong.us/alvinlollo/AlvinArch)
+          MDEOF
+
           git -C "$REPO_DIR" config user.name "Gitea Actions"
           git -C "$REPO_DIR" config user.email "actions@gitea.local"
-          git -C "$REPO_DIR" add .gitattributes "releases/$TAG_NAME"
+          git -C "$REPO_DIR" add .gitattributes README.md "releases/$TAG_NAME"
           if git -C "$REPO_DIR" diff --cached --quiet; then
             echo "⚠️  No changes to commit for $TAG_NAME — releasing as-is." >&2
           else
@@ -212,31 +226,52 @@ jobs:
 
           echo "  ✅ Released $TAG_NAME (ID: $RELEASE_ID) with download link + SHA-256 checksums"
 
+          # Mirror the release tag on the releases repo for redundancy/discovery
+          if ! git -C "$REPO_DIR" ls-remote --exit-code origin \
+              refs/tags/"$TAG_NAME" >/dev/null 2>&1; then
+            git -C "$REPO_DIR" tag "$TAG_NAME"
+            if ! git -C "$REPO_DIR" push --quiet origin "$TAG_NAME" 2>/dev/null; then
+              echo "❌ Failed to push tag $TAG_NAME to $RELEASES_REPO." >&2
+              exit 1
+            fi
+          fi
+          if ! curl -sf -o /dev/null -H "Authorization: token $GITEA_TOKEN" \
+              "$GITEA_API/repos/$RELEASES_REPO/releases/tags/$TAG_NAME"; then
+            curl -sf -X POST \
+              -H "Authorization: token $GITEA_TOKEN" \
+              -H "Content-Type: application/json" \
+              "$GITEA_API/repos/$RELEASES_REPO/releases" \
+              -d "$payload" > /dev/null
+            echo "  ✅ Mirrored $TAG_NAME release on $RELEASES_REPO"
+          fi
+
       - name: Keep only latest 3 releases
         if: success()
         env:
           GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
           GITEA_API: http://192.168.1.168:3000/api/v1
           REPOSITORY: ${{ github.repository }}
+          RELEASES_REPO: alvinlollo/AlvinArch-releases
         run: |
           set -euo pipefail
           test -n "$GITEA_TOKEN"
 
-          # Fetch all release ids, oldest first
-          readarray -t ids < <(curl -sf -H "Authorization: token $GITEA_TOKEN" \
-            "$GITEA_API/repos/$REPOSITORY/releases" \
-            | jq -er 'sort_by(.created_at) | .[].id')
+          for repo in "$REPOSITORY" "$RELEASES_REPO"; do
+            echo "Pruning old releases in $repo..."
+            readarray -t ids < <(curl -sf -H "Authorization: token $GITEA_TOKEN" \
+              "$GITEA_API/repos/$repo/releases" \
+              | jq -er 'sort_by(.created_at) | .[].id')
 
-          # Delete the oldest releases, keeping only the 3 newest
-          to_delete=$(( ${#ids[@]} - 3 ))
-          if (( to_delete > 0 )); then
-            for ((i = 0; i < to_delete; i++)); do
-              id=${ids[$i]}
-              echo "Deleting old release ID: $id"
-              curl -sf -X DELETE -H "Authorization: token $GITEA_TOKEN" \
-                "$GITEA_API/repos/$REPOSITORY/releases/$id"
-            done
-          fi
+            to_delete=$(( ${#ids[@]} - 3 ))
+            if (( to_delete > 0 )); then
+              for ((i = 0; i < to_delete; i++)); do
+                id=${ids[$i]}
+                echo "Deleting old release ID: $id (in $repo)"
+                curl -sf -X DELETE -H "Authorization: token $GITEA_TOKEN" \
+                  "$GITEA_API/repos/$repo/releases/$id"
+              done
+            fi
+          done
 
       - name: Cleanup mkarchiso mounts and workdirs
         if: always() # Runs on success, failure, or cancellation