Add Flatpak build support and env override for yt-dlp path

Introduces a Flatpak packaging step to the Linux CI workflow and updates ytsage_constants.py to support overriding the yt-dlp binary path via the YTDLP_APP_BIN_PATH environment variable, which is critical for Flatpak compatibility. Also ensures the custom yt-dlp directory is created if the environment variable is set.

.github/workflows/build-linux.yml

@@ -380,6 +380,84 @@ jobs:
         mv "$deb_out" artifacts/
         echo "Built native DEB: artifacts/$deb_out"
 
+    - name: Build Flatpak Bundle
+      shell: bash
+      run: |
+        version="${{ steps.get_version.outputs.VERSION }}"
+        
+        # Install flatpak-builder
+        sudo apt-get install -y flatpak-builder
+        flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
+
+        # Define manifest ID
+        APP_ID="io.github.oop7.YTSage"
+        
+        # Create manifest manually
+        cat > ytsage_flatpak.json <<EOF
+        {
+          "app-id": "$APP_ID",
+          "runtime": "org.kde.Platform",
+          "runtime-version": "6.6",
+          "sdk": "org.kde.Sdk",
+          "command": "ytsage",
+          "finish-args": [
+            "--share=ipc",
+            "--socket=x11",
+            "--socket=wayland",
+            "--socket=pulseaudio",
+            "--device=dri",
+            "--share=network",
+            "--filesystem=host",
+            "--env=YTDLP_APP_BIN_PATH=/var/data/yt-dlp"
+          ],
+          "modules": [
+            {
+              "name": "ytsage",
+              "buildsystem": "simple",
+              "build-commands": [
+                "mkdir -p /app/bin /app/share/ytsage",
+                "cp -r dist/ytsage-v${version}-*/* /app/share/ytsage/",
+                "ln -s /app/share/ytsage/ytsage /app/bin/ytsage",
+                "install -D ytsage.desktop /app/share/applications/$APP_ID.desktop",
+                "install -D assets/branding/icons/icon.png /app/share/icons/hicolor/128x128/apps/$APP_ID.png"
+              ],
+              "sources": [
+                {
+                  "type": "dir",
+                  "path": "."
+                }
+              ]
+            }
+          ]
+        }
+        EOF
+
+        # Build the Flatpak
+        # Note: In a real environment, building from source is preferred.
+        # Here we are "bundling" the already built binaries from the previous step (cx_Freeze) for simplicity in CI.
+        # This requires the 'dist/' folder to be populated by the previous 'Create cx_Freeze setup script' + build steps.
+        # Wait, the previous steps built into 'build/exe.linux-...' not 'dist/'. Let's find it.
+        
+        build_dir=$(ls -d build/exe.* 2>/dev/null | head -n1)
+        if [ -z "$build_dir" ]; then
+          echo "Error: build/exe.* directory not found for Flatpak build" >&2
+          exit 1
+        fi
+        
+        # Move build dir to a fixed location for the manifest source to catch
+        mkdir -p dist/ytsage-v${version}-flatpak
+        cp -r "$build_dir"/* "dist/ytsage-v${version}-flatpak/"
+        
+        # Install runtime/sdk
+        flatpak install -y --user flathub org.kde.Platform//6.6 org.kde.Sdk//6.6
+
+        # Build
+        flatpak-builder --user --install-deps-from=flathub --repo=repo --force-clean build-flatpak ytsage_flatpak.json
+        
+        # Bundle
+        flatpak build-bundle repo artifacts/YTSage-v${version}-x86_64.flatpak $APP_ID
+        echo "Built Flatpak: artifacts/YTSage-v${version}-x86_64.flatpak"
+
     - name: Package and prepare release artifacts (.AppImage, .rpm, .deb)
       shell: bash
       run: |
@@ -407,6 +485,9 @@ jobs:
         # DEB is already staged in artifacts by the native packaging step
         ls -1 artifacts/*.deb 2>/dev/null || echo "Warning: No .deb found in artifacts/"
 
+        # Check for Flatpak
+        ls -1 artifacts/*.flatpak 2>/dev/null || echo "Warning: No .flatpak found in artifacts/"
+
         echo "Final artifacts:"
         ls -lh artifacts || true