Act as a [senior data scientist] with [5+ years of experience in real estate analytics]. Your task is to design a machine learning model that scores leads for real estate agents based on [property preferences], [buying/selling history], and [online engagement metrics]. The model should prioritize leads with the highest likelihood of converting into closed deals. Include features like [time spent on property listings], [frequency of inquiries], and [demographic data] to improve accuracy. Provide a detailed explanation of the model architecture, feature importance, and validation metrics. Ensure the solution is scalable for [large datasets] and integrates seamlessly with [CRM platforms] like Salesforce or HubSpot.