Android launcher: drop monochrome (themed) icon, keep color only

The monochrome adaptive-icon layer produced a poor themed-icon rendering.
Remove the <monochrome> reference from mipmap-anydpi-v26/ic_launcher.xml and
delete the ic_launcher_monochrome.png files so Android always uses the color
adaptive icon (background + foreground). sync-android-sources.sh also drops any
monochrome layer Tauri regenerates.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/sync-android-sources.sh

@@ -65,6 +65,11 @@ if [ -d "$RES_SRC" ]; then
         cp "$dir"/* "$RES_DST/$name/"
         echo "  Copied res: $name"
     done
+    # We ship only the color adaptive icon (background + foreground). Drop any
+    # monochrome layer Tauri may generate: the themed-icon monochrome doesn't
+    # render well, and our adaptive-icon xml no longer references it, so a stray
+    # ic_launcher_monochrome.png would just be dead weight.
+    rm -f "$RES_DST"/mipmap-*/ic_launcher_monochrome.png
 fi
 
 echo "✓ Android sources synced successfully"