Move templates and assets to templates/ folder

- Move all HTML templates to templates/
- Move Platinum assets to templates/Platinum/
- Update default paths in generate_report.py

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

generate_report.py

@@ -177,8 +177,8 @@ def main():
     )
     parser.add_argument(
         "--assets",
-        default="Platinum",
-        help="Path to Platinum assets directory (default: Platinum)"
+        default="templates/Platinum",
+        help="Path to Platinum assets directory (default: templates/Platinum)"
     )
     parser.add_argument(
         "--background",
@@ -187,8 +187,8 @@ def main():
     )
     parser.add_argument(
         "--template",
-        default="platinum.html",
-        help="HTML template file to use (default: platinum.html)"
+        default="templates/platinum.html",
+        help="HTML template file to use (default: templates/platinum.html)"
     )
 
     args = parser.parse_args()