Add boss battle sprites, badge images, and fix seed data

- Download boss battle sprites from Bulbapedia for all 21 games (313 bosses)
- Download 36 missing badge images from Bulbapedia archives
- Fix non-square boss sprite stretching (use h-10 w-auto instead of w-10 h-10)
- Fix firered Giovanni seed data (badge was "50" instead of "Earth Badge",
  missing ground specialty_type)
- Add one-time fetch scripts for boss sprites and badges

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

backend/src/app/seeds/data/scarlet-bosses.json

@@ -276,7 +276,7 @@
     "after_route_name": null,
     "location": "South Province (Area Three)",
     "section": "Path of Legends",
-    "sprite_url": "/boss-sprites/scarlet/stony-cliff-titan.png",
+    "sprite_url": "/sprites/950.webp",
     "pokemon": []
   },
   {
@@ -290,7 +290,7 @@
     "after_route_name": null,
     "location": "West Province (Area One)",
     "section": "Path of Legends",
-    "sprite_url": "/boss-sprites/scarlet/open-sky-titan.png",
+    "sprite_url": "/sprites/962.webp",
     "pokemon": []
   },
   {
@@ -304,7 +304,7 @@
     "after_route_name": null,
     "location": "East Province (Area Three)",
     "section": "Path of Legends",
-    "sprite_url": "/boss-sprites/scarlet/lurking-steel-titan.png",
+    "sprite_url": "/sprites/968.webp",
     "pokemon": []
   },
   {
@@ -318,7 +318,7 @@
     "after_route_name": null,
     "location": "Asado Desert",
     "section": "Path of Legends",
-    "sprite_url": "/boss-sprites/scarlet/quaking-earth-titan.png",
+    "sprite_url": "/sprites/984.webp",
     "pokemon": []
   },
   {
@@ -332,7 +332,7 @@
     "after_route_name": null,
     "location": "Casseroya Lake",
     "section": "Path of Legends",
-    "sprite_url": "/boss-sprites/scarlet/false-dragon-titan.png",
+    "sprite_url": "/sprites/977.webp",
     "pokemon": []
   }
 ]