rename: JarvisIcon -> JervisIcon asset (splash screen)

Same radar-rings artwork, just the asset name catching up to the
Jervis rebrand. No visual change.

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

Jarvis/Assets.xcassets/JervisIcon.imageset/Contents.json

@@ -1,7 +1,7 @@
 {
   "images" : [
     {
-      "filename" : "JarvisIcon.png",
+      "filename" : "JervisIcon.png",
       "idiom" : "universal",
       "scale" : "1x"
     },