Update asset paths in build workflows

Changed asset inclusion and screenshot removal paths from 'assets' to 'lib/assets' in Linux, macOS, and Windows build workflows to reflect new directory structure and ensure screenshots are excluded from packaged builds.

.github/workflows/build-linux.yml

@@ -122,7 +122,7 @@ jobs:
             ],
             include_files=[
                 ("src", "src"),
-                ("assets", "assets"),
+                ("assets", "lib/assets"),
                 ("ytsage.desktop", "share/applications/ytsage.desktop"),
                 ("assets/branding/icons/icon.png", "share/pixmaps/ytsage.png"),
             ],
@@ -185,8 +185,8 @@ jobs:
 
         # Remove screenshots to reduce size before packaging
         build_dir=$(ls -d build/exe.* 2>/dev/null | head -n1 || true)
-        if [ -n "$build_dir" ] && [ -d "$build_dir/assets/branding/screenshots" ]; then
-          rm -rf "$build_dir/assets/branding/screenshots"
+        if [ -n "$build_dir" ] && [ -d "$build_dir/lib/assets/branding/screenshots" ]; then
+          rm -rf "$build_dir/lib/assets/branding/screenshots"
           echo "Removed screenshots folder from $build_dir"
         fi