Temporal Coherence as a Selection Principle in Time-Scalar Field Theory (TSFT): Rivet Stability, Particle Persistence, and Observation as a Coherence Operator

We develop a non-anthropic, dynamical resolution of apparent fine-tuning within Time-Scalar Field Theory (TSFT) by introducing a Temporal Coherence Principle (TCP): only regimes that sustain continuous propagation of structured information across scalar-time gradients persist as physically realized dynamics. Building on the Froggle Dilemma framework, we formalize rivets as discrete microphysical phase-anchoring structures that stabilize local coherence under temporal shear, with explicit stability and failure regimes illustrated by bounded and diverging phase trajectories. Particles are then defined as localized persistence eigenmodes supported by rivet coherence rather than primitive ontological entities. We further show that observation is not an emergent property of aggregation, but a dynamical regime in which internal temporal modeling (interiority) enables ensemble-level coherence regulation across future scalar-time evolution. Finally, we argue that closed scalar-time manifolds require internal coherence restoration at cosmological scale, implying maximal interiority (maximal aw areness) as a closure condition for long-horizon persistence of structured universes. In this framework, dimensionless and effective coupling parameters arise as stability-band eigenvalues of rivet survival under scalar-time stress rather than as independently tunable constants, while observers emerge as coherence regulators necessitated by the persistence of complex systems.