ci(flatpak): add Flatpak support with metainfo and asset validation

Entire-Checkpoint: 21b9b9f90f23

.github/workflows/build-and-make.yaml

@@ -49,7 +49,7 @@ jobs:
               if: matrix.os == 'linux'
               run: |
                   sudo apt-get update
-                  sudo apt-get install --no-install-recommends -y rpm libarchive-tools flatpak flatpak-builder
+                  sudo apt-get install --no-install-recommends -y rpm libarchive-tools flatpak flatpak-builder appstream
 
                   # Configure Flatpak
                   # 1. Add the Flathub repository (source of runtimes)
@@ -68,6 +68,27 @@ jobs:
             - name: Build backend
               run: pnpm run build:backend
 
+            - name: Validate AppStream metadata
+              if: matrix.os == 'linux'
+              run: appstreamcli validate --pedantic --no-net apps/electron-backend/linux/com.fourgray.iptvnator.metainfo.xml
+
+            - name: Build website
+              if: matrix.os == 'linux'
+              run: pnpm nx build website --skip-nx-cache
+
+            - name: Verify AppStream website assets
+              if: matrix.os == 'linux'
+              shell: bash
+              run: |
+                  set -euo pipefail
+
+                  for screenshot in player playlists epg settings; do
+                      if ! find dist/apps/website -path "*/appstream/${screenshot}.png" -print -quit | grep -q .; then
+                          echo "::error::Missing AppStream website asset for ${screenshot}.png"
+                          exit 1
+                      fi
+                  done
+
             - name: Override macOS arch in electron-builder.json
               if: matrix.os == 'macos'
               run: |
@@ -241,6 +262,7 @@ jobs:
                   fi
 
                   flatpak install --user --noninteractive -y "${FLATPAK_BUNDLE}"
+                  flatpak run --command=sh com.fourgray.iptvnator -c 'test -f /app/share/metainfo/com.fourgray.iptvnator.metainfo.xml'
                   flatpak run --command=sh com.fourgray.iptvnator -c '/app/bin/iptvnator --version'
 
             - name: Upload artifacts (macOS)