add taskbar icon with dark circle background

Logo SVGs made square (160x160). New onbackground variant has the
clide logo on a #20202C filled circle. Rendered at 1024px and
downsampled to 256/128/48 for crisp taskbar icons. Native runner
loads clide-taskbar-256.png instead of the bare logo.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

assets/logo/clide-logo-onbackground.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 160 160" width="160" height="160">
+  <circle cx="80" cy="80" r="72" fill="#20202C"/>
+  <g fill="none" stroke-linecap="round" stroke-linejoin="round" transform="translate(-20,0)">
+    <polyline points="89,55 66,80 89,105" stroke="#5691a1" stroke-width="8"/>
+    <polyline points="111,55 134,80 111,105" stroke="#33404c" stroke-width="8"/>
+    <line x1="100" y1="118" x2="134" y2="118" stroke="#d97757" stroke-width="5"/>
+  </g>
+</svg>

assets/logo/clide-logo.svg

@@ -1,5 +1,5 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 160" width="200" height="160">
-  <g fill="none" stroke-linecap="round" stroke-linejoin="round">
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 160 160" width="160" height="160">
+  <g fill="none" stroke-linecap="round" stroke-linejoin="round" transform="translate(-20,0)">
     <polyline points="89,55 66,80 89,105" stroke="#5691a1" stroke-width="8"/>
     <polyline points="111,55 134,80 111,105" stroke="#33404c" stroke-width="8"/>
     <line x1="100" y1="118" x2="134" y2="118" stroke="#d97757" stroke-width="5"/>

linux/runner/my_application.cc

@@ -123,7 +123,7 @@ static void my_application_activate(GApplication* application) {
       g_autofree gchar* exe_dir = g_path_get_dirname(exe_path);
       g_autofree gchar* icon_path = g_build_filename(
           exe_dir, "data", "flutter_assets", "assets", "logo",
-          "clide-logo-256.png", nullptr);
+          "clide-taskbar-256.png", nullptr);
       g_autoptr(GError) icon_error = nullptr;
       GdkPixbuf* icon = gdk_pixbuf_new_from_file(icon_path, &icon_error);
       if (icon != nullptr) {