Update to math-olympiad

{
  "official": [
    {
      "name": "math-olympiad",
      "author": {
        "name": "Anthropic",
        "email": "support@anthropic.com"
      },
      "source": "./plugins/math-olympiad",
      "category": "math",
      "homepage": "https://github.com/anthropics/claude-plugins-official/tree/main/plugins/math-olympiad",
      "description": "Solve competition math (IMO, Putnam, USAMO) with adversarial verification that catches what self-verification misses. Fresh-context verifiers attack proofs with specific failure patterns. Calibrated abstention over bluffing."
    }
  ]
}