Add Linux arm64 release binary and .deb package

Adds an ubuntu-24.04-arm matrix entry so each release produces
mdcms-linux-arm64 and a matching arm64 .deb alongside the existing
amd64 artefacts. Fixes the fpm binary path and .deb artifact name to
be matrix-driven so both Linux builds are independent.

https://claude.ai/code/session_01LScjwzJJgLKsNrqEPLxJS8

.github/workflows/release.yml

@@ -31,6 +31,12 @@ jobs:
             artifact_name: mdcms-macos-arm64
             make_deb: false
 
+          - os: ubuntu-24.04-arm
+            label: Linux arm64
+            binary_name: mdcms
+            artifact_name: mdcms-linux-arm64
+            make_deb: true
+
           - os: windows-latest
             label: Windows amd64
             binary_name: mdcms.exe
@@ -71,9 +77,9 @@ jobs:
             --url "https://github.com/kbenestad/mdcms" \
             --maintainer "Kristian Benestad" \
             --license "Apache-2.0" \
-            --architecture amd64 \
+            --architecture "${{ matrix.os == 'ubuntu-24.04-arm' && 'arm64' || 'amd64' }}" \
             --category utils \
-            dist/mdcms-linux-amd64=/usr/local/bin/mdcms
+            dist/${{ matrix.artifact_name }}=/usr/local/bin/mdcms
 
       - name: Upload binary artifact
         uses: actions/upload-artifact@v4
@@ -88,7 +94,7 @@ jobs:
         if: matrix.make_deb
         uses: actions/upload-artifact@v4
         with:
-          name: deb-package
+          name: deb-package-${{ matrix.artifact_name }}
           path: "*.deb"
 
   release:
@@ -120,6 +126,8 @@ jobs:
             --generate-notes \
             $PRERELEASE \
             artifacts/mdcms-linux-amd64/mdcms-linux-amd64 \
+            artifacts/mdcms-linux-arm64/mdcms-linux-arm64 \
             artifacts/mdcms-macos-arm64/mdcms-macos-arm64 \
             artifacts/mdcms-windows-amd64/mdcms-windows-amd64.exe \
-            artifacts/deb-package/*.deb
+            artifacts/deb-package-mdcms-linux-amd64/*.deb \
+            artifacts/deb-package-mdcms-linux-arm64/*.deb