Dual-Mode Drift Control in Phase-Governed Autonomous Systems: Continuous Curvature and Intermediate-Axis Instability

Description This work introduces a geometric framework for controlling behavioral drift in phase-governed autonomous systems. Two structural deviation modes are analyzed: Continuous curvature drift caused by bias anisotropy amplified through recursive feedback. Catastrophic orientation shifts analogous to intermediate-axis instability in rigid body dynamics. The paper derives formal metrics for both modes and proposes a pre-action stability monitor that performs local anisotropy suppression and governance-axis rebalancing before irreversible actions. The framework is architecture-agnostic and suitable for integration into layered AI safety systems. Implementation details are intentionally abstracted to preserve internal design integrity.