Variational Backbone and Regime Closures XII (UV): Principal-Operator Invariance and Collapse-Route Exclusion Exterior-gate GR, summary-active interior readouts, and period-charge barriers

This paper treats collapse-route exclusion in VBRC as a gated interface diagnostic, not as an unrestricted singularity-resolution claim. Following the Part I constitutional order, Part XII first declares its instance package, then licenses an unread-to-retained summary channel. Only inside a selected representative branch may this summary be written in a first-order form. The diagnostic studied here is a form-valued period readout of the licensed summary. The associated period charge is not a universal primitive datum of the unread sector, but a branch-level readout obtained from a declared period representative. Part XII also separates two geometric gates: ordinary exterior general relativity is treated as a summary-suppressed readout, while a black-hole interior readout may be summary-active. The main result is conditional. If the declared period charge is nonzero, the localized period-coercivity gate is active, and a finite R2/R3 budget gate remains valid, then the route in which the declared cycle volume collapses to zero is not licensed. This is a branch-internal barrier theorem inside the declared Part XII instance. It is not a universal no-singularity theorem, and it does not address charge-null sectors, Hawking evaporation, information loss, or cosmological initial singularities outside the declared gates.