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/JourneyView.svelte

@@ -5,7 +5,7 @@
   import worldData from 'world-atlas/countries-50m.json';
   import { get } from 'svelte/store';
   import { journals } from '../stores/journalStore.js';
-  import airplaneImg from '../../assets/animationPlane.png';
+  import airplaneImg from '../../assets/airplane.png';
 
   let { onclose, onprogress, mode = 'map', onmodechange } = $props();