Clean up frontend branding and metadata

Replace Vite defaults with Nuzlocke Tracker branding: custom pokeball-
skull favicon (SVG + PNG + ICO), page title, meta description, Open
Graph tags, theme-color, web manifest, and package.json name.

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

frontend/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "frontend",
+  "name": "nuzlocke-tracker-frontend",
   "private": true,
   "version": "0.0.0",
   "type": "module",