ci(health-check): rewire cache to match docker-new restructure (#7032)

* ci(health-check): rewire cache to match docker-new restructure

- Switch buildcache-new tag to its own scope
  `health-check-<build-type>-humble-<platform>-<ref>` (instead of the
  ci-universe tags that no longer populate), with current-ref + main
  fallback reads and a current-ref write, mirroring
  docker-build-new.yaml's pattern.
- Add read-only `buildkit-cache-dance` injection fed by the
  `buildkit-mounts-ci-universe-humble-<platform>-*` tarballs the main
  pipeline saves, so health-check reuses the same apt / ccache / pip /
  pipx mount state without writing back.

Signed-off-by: Mete Fatih Cırıt <mfc@autoware.org>

* docs(health-check): shorten cache-restore comment

Signed-off-by: Mete Fatih Cırıt <mfc@autoware.org>

Author: xmfcx

.github/workflows/health-check-reusable.yaml

@@ -29,6 +29,10 @@ jobs:
       - name: 📥 Check out repository
         uses: actions/checkout@v6
 
+      - name: 🏷️ Compute cache ref
+        id: meta
+        run: echo "ref_name=${GITHUB_REF_NAME//\//-}" >> "$GITHUB_OUTPUT"
+
       - name: 💻 Runner specs
         run: |
           echo "::group::CPU"
@@ -72,6 +76,50 @@ jobs:
             [worker.oci]
               max-parallelism = 2
 
+      # Read-only: reuses the mount cache saved by docker-new's `ci-universe` group.
+      - name: 💾 Restore BuildKit cache mounts (read-only)
+        id: cache-restore
+        uses: actions/cache/restore@v5
+        with:
+          path: cache-mounts
+          key: buildkit-mounts-ci-universe-humble-${{ matrix.platform }}-${{ github.sha }}
+          restore-keys: |
+            buildkit-mounts-ci-universe-humble-${{ matrix.platform }}-
+
+      - name: 💉 Inject BuildKit cache mounts
+        uses: reproducible-containers/buildkit-cache-dance@v3
+        with:
+          cache-map: |
+            {
+              "cache-mounts/apt-cache": {
+                "id": "apt-cache-humble",
+                "target": "/var/cache/apt"
+              },
+              "cache-mounts/apt-lists": {
+                "id": "apt-lists-humble",
+                "target": "/var/lib/apt/lists"
+              },
+              "cache-mounts/ccache": {
+                "id": "ccache-humble",
+                "target": "/home/aw/.ccache",
+                "uid": "1000",
+                "gid": "1000"
+              },
+              "cache-mounts/pip": {
+                "id": "pip-cache",
+                "target": "/home/aw/.cache/pip",
+                "uid": "1000",
+                "gid": "1000"
+              },
+              "cache-mounts/pipx": {
+                "id": "pipx-cache",
+                "target": "/home/aw/.cache/pipx",
+                "uid": "1000",
+                "gid": "1000"
+              }
+            }
+          skip-extraction: ${{ steps.cache-restore.outputs.cache-hit }}
+
       - name: 🔑 Login to GitHub Container Registry
         uses: docker/login-action@v4
         with:
@@ -89,8 +137,9 @@ jobs:
           files: docker-new/docker-bake.hcl
           provenance: false
           set: |
-            *.cache-from=type=registry,ref=ghcr.io/${{ github.repository }}-buildcache-new:humble-${{ matrix.platform }}-main
-            *.cache-from=type=registry,ref=ghcr.io/${{ github.repository }}-buildcache-new:${{ matrix.build-type }}-humble-${{ matrix.platform }}-main
+            *.cache-from=type=registry,ref=ghcr.io/${{ github.repository }}-buildcache-new:health-check-${{ matrix.build-type }}-humble-${{ matrix.platform }}-${{ steps.meta.outputs.ref_name }}
+            *.cache-from=type=registry,ref=ghcr.io/${{ github.repository }}-buildcache-new:health-check-${{ matrix.build-type }}-humble-${{ matrix.platform }}-main
+            *.cache-to=type=registry,ref=ghcr.io/${{ github.repository }}-buildcache-new:health-check-${{ matrix.build-type }}-humble-${{ matrix.platform }}-${{ steps.meta.outputs.ref_name }},mode=max,ignore-error=true
 
       - name: 📊 Disk space
         if: always()