Add app icons, screenshots, and complete AppStream metainfo

- Add GNOME HIG-compliant app icon (scalable SVG) and symbolic variant
- Add 12 screenshots covering all major views and features
- Flesh out metainfo with screenshots, categories, URLs, content
  rating, system requirements, provides, translation, donation
  and contact links
- Update AppImage build script to bundle GTK plugin, symbolic
  icon, and metainfo
- Update meson.build with icon installation rules
- Remove About dialog from application menu
- Remove unused user guide and audit tool

packaging/build-appimage.sh

@@ -29,6 +29,8 @@ mkdir -p "$APPDIR/usr/bin"
 mkdir -p "$APPDIR/usr/share/applications"
 mkdir -p "$APPDIR/usr/share/glib-2.0/schemas"
 mkdir -p "$APPDIR/usr/share/icons/hicolor/scalable/apps"
+mkdir -p "$APPDIR/usr/share/icons/hicolor/symbolic/apps"
+mkdir -p "$APPDIR/usr/share/metainfo"
 
 # Binary
 cp "target/release/driftwood" "$APPDIR/usr/bin/driftwood"
@@ -40,8 +42,8 @@ cp "data/$APP_ID.desktop" "$APPDIR/usr/share/applications/$APP_ID.desktop"
 cp "data/$APP_ID.gschema.xml" "$APPDIR/usr/share/glib-2.0/schemas/$APP_ID.gschema.xml"
 glib-compile-schemas "$APPDIR/usr/share/glib-2.0/schemas/"
 
-# Icon - use a placeholder SVG if no real icon exists yet
-ICON_FILE="data/icons/$APP_ID.svg"
+# Icon
+ICON_FILE="data/icons/hicolor/scalable/apps/$APP_ID.svg"
 if [ -f "$ICON_FILE" ]; then
     cp "$ICON_FILE" "$APPDIR/usr/share/icons/hicolor/scalable/apps/$APP_ID.svg"
 else
@@ -56,6 +58,18 @@ else
 SVGEOF
 fi
 
+# Symbolic icon
+SYMBOLIC_FILE="data/icons/hicolor/symbolic/apps/$APP_ID-symbolic.svg"
+if [ -f "$SYMBOLIC_FILE" ]; then
+    cp "$SYMBOLIC_FILE" "$APPDIR/usr/share/icons/hicolor/symbolic/apps/$APP_ID-symbolic.svg"
+fi
+
+# AppStream metainfo
+METAINFO_FILE="data/$APP_ID.metainfo.xml"
+if [ -f "$METAINFO_FILE" ]; then
+    cp "$METAINFO_FILE" "$APPDIR/usr/share/metainfo/$APP_ID.metainfo.xml"
+fi
+
 # Check for linuxdeploy
 LINUXDEPLOY="${LINUXDEPLOY:-linuxdeploy}"
 if ! command -v "$LINUXDEPLOY" &>/dev/null; then
@@ -77,20 +91,20 @@ if ! command -v "$LINUXDEPLOY" &>/dev/null; then
 fi
 
 # Check for GTK plugin
-GTK_PLUGIN="${LINUXDEPLOY_PLUGIN_GTK:-}"
-if [ -z "$GTK_PLUGIN" ]; then
-    if [ -x "./linuxdeploy-plugin-gtk.sh" ]; then
-        export DEPLOY_GTK_VERSION=4
-    else
-        echo ""
-        echo "Warning: linuxdeploy-plugin-gtk not found."
-        echo "GTK4 libraries will not be bundled."
-        echo "The AppImage may only work on systems with GTK4 and libadwaita installed."
-        echo ""
-        echo "Download the plugin from:"
-        echo "  https://github.com/nickvdp/linuxdeploy-plugin-gtk"
-        echo ""
-    fi
+GTK_PLUGIN_ARG=""
+if [ -x "./linuxdeploy-plugin-gtk.sh" ]; then
+    export DEPLOY_GTK_VERSION=4
+    GTK_PLUGIN_ARG="--plugin gtk"
+    echo "GTK4 plugin found - libraries will be bundled."
+else
+    echo ""
+    echo "Warning: linuxdeploy-plugin-gtk not found."
+    echo "GTK4 libraries will not be bundled."
+    echo "The AppImage may only work on systems with GTK4 and libadwaita installed."
+    echo ""
+    echo "Download the plugin from:"
+    echo "  https://github.com/linuxdeploy/linuxdeploy-plugin-gtk"
+    echo ""
 fi
 
 echo "=== Building AppImage ==="
@@ -102,6 +116,7 @@ export GSETTINGS_SCHEMA_DIR="$APPDIR/usr/share/glib-2.0/schemas"
     --appdir "$APPDIR" \
     --desktop-file "$APPDIR/usr/share/applications/$APP_ID.desktop" \
     --icon-file "$APPDIR/usr/share/icons/hicolor/scalable/apps/$APP_ID.svg" \
+    $GTK_PLUGIN_ARG \
     --output appimage
 
 echo ""