Perform a threat model for a new smart home IoT hub that connects via Wi-Fi and controls Zigbee lights. Use the STRIDE methodology (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege). Identify the top 3 most critical vulnerabilities for each data flow (e.g., Mobile App to Cloud, Cloud to Hub, Hub to Device). Propose specific mitigation controls for the highest-risk threats identified.