Run slice check on arm64 Linux

.github/workflows/build_all.yml

@@ -172,17 +172,17 @@ jobs:
   # binary); this covers src/engine PRs with the PR-built binary. Runs in
   # parallel off build_linux's artifact so it doesn't lengthen the build leg.
   slice_check_linux:
-    name: Slice check (Linux x86_64)
+    name: Slice check (Linux aarch64)
     needs: build_linux
     if: ${{ !cancelled() && success() }}
-    runs-on: ${{ vars.SELF_HOSTED && 'orca-lnx-server' || 'ubuntu-24.04' }}
+    runs-on: ubuntu-24.04-arm
     steps:
       - name: Checkout repository
         uses: actions/checkout@v7
       - name: Download profile validator
         uses: actions/download-artifact@v8
         with:
-          name: ${{ github.sha }}-profile-validator-linux-x86_64
+          name: ${{ github.sha }}-profile-validator-linux-aarch64
           path: validator-bin
       - name: Validate slice (expand custom g-code)
         timeout-minutes: 60

.github/workflows/build_orca.yml

@@ -510,13 +510,15 @@ jobs:
 
         # Ship the freshly-built validator so the parallel slice_check_linux job
         # (build_all.yml) can slice-sweep the shipped profiles with this PR's
-        # engine. Stable sha-based name mirrors the tests artifact above so the
+        # engine. Taken from the aarch64 leg so the sweep runs on arm64 (its
+        # GitHub-hosted runner is free, and it also exercises the arm build).
+        # Stable sha-based name mirrors the tests artifact above so the
         # downstream job downloads it by exact name.
       - name: Upload profile validator (for slice check)
-        if: runner.os == 'Linux' && inputs.arch != 'aarch64'
+        if: runner.os == 'Linux' && inputs.arch == 'aarch64'
         uses: actions/upload-artifact@v7
         with:
-          name: ${{ github.sha }}-profile-validator-linux-x86_64
+          name: ${{ github.sha }}-profile-validator-linux-aarch64
           overwrite: true
           path: ./build/src/Release/OrcaSlicer_profile_validator
           retention-days: 5