MCP tool usage stats

curl --request GET \
  --url https://api.example.com/api/admin/analytics/tools \
  --header 'Authorization: Bearer <token>'

{
  "tools": [
    {
      "tool_name": "<string>",
      "call_count": 123,
      "avg_duration_ms": 123,
      "error_rate_pct": 123
    }
  ],
  "total_calls": 123,
  "days": 123
}