Fix platform for GPU Mode competition

Author: hcarlens

competitions.json

@@ -37,7 +37,7 @@
       "registration-deadline": "30 Mar 2026",
       "deadline": "11 May 2026 Apr 2026",
       "prize": "$1,100,000",
-      "platform": "CrunchDAO",
+      "platform": "Independent",
       "sponsor": "AMD, GPU Mode",
       "conference": null,
       "conference_year": null