fix: Update-Skript, Containerfile-Optimierungen und chunkah-Rechunking

- notify-bootc-user.sh: D-Bus-Umgebung korrekt fuer Systemd-Service,
  jq-basierter Staging-Check (.status.staged != null), Guard Clauses,
  -Variable entfernt
- Containerfile: COPY --chmod=755 fuer Skript-Permissions
- build/20-multimedia.sh: Redundantes dnf5 clean all entfernt
- build/30-virt.sh: dnf5 autoremove und Cleanup entfernt
- build/40-remove-packages.sh: || true entfernt (Fehler sichtbar machen)
- build/50-prepare-flatpak-for-bazaar.sh: curl -f --retry 3 hinzugefuegt
- build.yml: chunkah Rechunk-Step fuer content-based Layers (Delta-Updates),
  Cache-Key erweitert (scripts/**), continue-on-error entfernt
- build-installer-iso.yml: concurrency-Block hinzugefuegt

.github/workflows/build-installer-iso.yml

@@ -3,6 +3,10 @@ name: Build Installer ISO
 on:
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build-iso:
     runs-on: ubuntu-latest

.github/workflows/build.yml

@@ -39,7 +39,6 @@ jobs:
       - name: Mount BTRFS for podman storage
         id: container-storage-action
         uses: ublue-os/container-storage-action@911baca08baf30c8654933e9e9723cb399892140 # main
-        continue-on-error: true 
         with:
           target-dir: /var/lib/containers
           mount-opts: compress-force=zstd:2
@@ -75,9 +74,9 @@ jobs:
             /var/lib/containers/storage/overlay
             ~/.cache/buildah
             /tmp/.buildah-cache
-          key: ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile', 'build/**', 'configs/**') }}-${{ github.ref }}
+          key: ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile', 'build/**', 'configs/**', 'scripts/**') }}-${{ github.ref }}
           restore-keys: |
-            ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile', 'build/**', 'configs/**') }}-
+            ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile', 'build/**', 'configs/**', 'scripts/**') }}-
             ${{ runner.os }}-${{ github.workflow }}-
 
       - name: Build Image
@@ -91,6 +90,32 @@ jobs:
           labels: ${{ steps.metadata.outputs.labels }}
           oci: true
 
+      - name: Rechunk with chunkah
+        run: |
+          set -euo pipefail
+
+          IMG="localhost/${{ env.IMAGE_NAME }}:${{ env.DEFAULT_TAG }}"
+          CHUNKED_IMG="localhost/${{ env.IMAGE_NAME }}-chunked:${{ env.DEFAULT_TAG }}"
+
+          # Image-Config fuer chunkah sichern (Labels, Annotations, etc.)
+          CONFIG=$(sudo buildah inspect "$IMG" | jq -c .)
+
+          # chunkah: content-based Layer-Splitting
+          # --max-layers 128: Desktop-Images brauchen mehr als Default (64)
+          # --prune /sysroot/: entfernt OSTree-Metadaten (optional seit bootc 1.1.3)
+          # --label ostree.*: entfernt gueltigkeitsfaehige ostree-Labels
+          sudo buildah build --skip-unused-stages=false \
+            --from "$IMG" \
+            --build-arg CHUNKAH_CONFIG_STR="$CONFIG" \
+            --build-arg "CHUNKAH_ARGS=--prune /sysroot/ --max-layers 128 --label ostree.commit- --label ostree.final-diffid-" \
+            -t "$CHUNKED_IMG" \
+            https://github.com/coreos/chunkah/releases/download/v0.5.0/Containerfile.splitter
+
+          # Platz freigeben: Original und Zwischenprodukt entfernen
+          sudo buildah rmi "$IMG"
+          sudo buildah tag "$CHUNKED_IMG" "$IMG"
+          sudo buildah rmi "$CHUNKED_IMG"
+
       - name: Login to GitHub Container Registry
         uses: docker/login-action@650006c6eb7dba73a995cc03b0b2d7f5ca915bee # v3
         if: github.event_name != 'pull_request' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch)