Act as a Principal Software Architect. Analyze a hypothetical monolithic application characterized by tight coupling, global state management, and lack of test coverage. Develop a high-level refactoring roadmap that transitions the codebase to a modular, event-driven architecture. Your strategy must address: 1) The identification and prioritization of critical 'strangler fig' candidates for extraction. 2) Methods for breaking circular dependencies without introducing breaking changes. 3) A plan for introducing continuous integration/testing where none exists. 4) Risk mitigation strategies for deploying refactored modules to production. Avoid writing specific code snippets; focus on architectural patterns, organizational strategies, and process changes.