Cyber↔Fusion↔QC: Quantum Engineering as the Substrate Spine of the Continuity Architecture

Quantum engineering provides the acceleration spine required to extend the Cyber↔Fusion substrate into the high‑dimensional continuity regime demanded by the Knowledge Age. Classical silicon substrates saturate under cyber workloads and energy‑continuity requirements, while fusion‑aligned systems require geometric acceleration beyond deterministic computation. Quantum computing offers this acceleration through the continuity of quantum state evolution, enabling identity continuity, energy continuity, and geometric continuity to coexist within a unified substrate architecture. Paper 10.11 establishes the Cyber↔Fusion↔QC triad as the substrate spine of continuity geometry, formalizes quantum engineering as the discipline that stabilizes quantum state transitions, defines the geometric invariants of quantum computation, and anchors the value‑chain inversion that emerges when continuity becomes the primary economic substrate. It also introduces the civilization‑M5‑level vessel architecture that emerges when quantum engineering becomes the dominant acceleration spine. This paper forms the foundation for the 10.x series and the continuity substrate of the Knowledge Age.