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

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "filename" : "JervisIcon.png",
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}