The explosive growth of the Internet of Things (IoT) presents unprecedented challenges in maintaining operational resilience, ensuring data privacy, and meeting regulatory compliance, particularly in distributed and mission-critical applications. This paper explores a robust IoT system architecture that leverages edge-cloud synergy to address these challenges. By integrating edge computing for local processing and cloud platforms for scalable storage and analytics, the proposed architecture enables uninterrupted operations during network disruptions and supports latency-sensitive tasks. Additionally, it enhances data sovereignty by enforcing privacy policies at the edge, reducing exposure of sensitive information to centralized servers. The framework also incorporates compliance-aware modules that adapt to dynamic regulatory requirements such as GDPR and HIPAA. Simulation and prototype evaluations demonstrate the architecture's effectiveness in sustaining operations during disconnections, reducing cloud dependency by over 40%, and maintaining strict privacy controls without compromising system performance. These findings establish edge-cloud synergy as a critical enabler for resilient, secure, and regulation-compliant IoT deployments in smart cities, healthcare, and industrial automation.