fix: use logo-signin, consolidate plane asset, fix home marker on resize

- Sign-in page now uses logo-signin.png
- World map animation uses airplane.png; remove unused animationPlane.png
- Re-project home marker on map resize so it stays correct when stats panel collapses

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/world-map/WorldMap.svelte

@@ -257,6 +257,7 @@
         countryPaths.attr('d', path);
         updateFill(countryPaths);
         renderMicrostates();
+        updateHomeMarker(getUserProfile()?.homeCountry ?? null);
       }
     });