feat(ci): Add unique artifact naming with SAFE_VER environment variable

Update kernel build workflow to use a path-friendly version name for
artifact naming. This ensures artifact names remain unique and avoids
issues with colon characters. Added SAFE_VER to GITHUB_ENV for reuse.

.gitea/workflows/build-kernel.yml

@@ -69,13 +69,15 @@ jobs:
           echo "kernel version $ver -> file modules/iec_listener_${safe}.ko"
           mkdir -p out/modules
           mv iec_listener.ko "out/modules/iec_listener_${safe}.ko"
+          # Expose the path-friendly name for the (colon-rejecting) artifact name.
+          echo "SAFE_VER=$safe" >> "$GITHUB_ENV"
 
       - name: Upload build output
         uses: https://github.com/christopherHX/gitea-upload-artifact@v4
         with:
           # Name by the path-friendly version so artifact names stay unique; all
           # of them merge back into the single modules/ folder at download time.
-          name: ${{ matrix.kernel_version }}
+          name: ${{ env.SAFE_VER }}
           path: kernel/out
           if-no-files-found: error