Bilateral Constitutive Dependence and the Boundary to Confinement in Registration Theory: Exact Constituent Non-Autonomy, Consequence-Minimal Host-Boundary Closure, and Open Frontier-Creation Correspondence

Registration Theory (RT) takes consequential bilateral registration, retained history, and continuing host-relative constitution as the starting ontology. This preprint tests whether an internally differentiated constituent in canonical ACRF-4 admits a consequence-complete autonomous successor independent of its participating host. Using the unchanged native successor and the previously established persistent zero-current-boundary-field sector, it constructs states with identical intrinsic constituent data and identical retained couplings but different receiving-host currents. The constituent's permutation-invariant next mean current has nonzero host-response derivative 0.05820440422888..., proving that no autonomous successor factors through the standard intrinsic constituent description over the admitted encounter family. Reciprocal retained-history sensitivity is also exact: differentiating the constituent changes the receiver's retained coupling with derivative 0.02231987331529..., despite the closed current-boundary field. The preprint combines these new analytic results with previously published interval-certified rank-nine joint host-consequence minimality and boundary-response reconstruction results, carefully distinguishing intrinsic non-autonomy from the stronger, unproved impossibility of every independently constituted physical constituent. A restricted native closure sector retains an autonomous reduced description, providing an explicit limitation on overbroad confinement claims. The RT_c null-frontier connection, compulsory daughter constitution, spatial creation, and physical quark confinement are formulated as open reconstruction targets, not established results. The PDF is accompanied by a standalone Python native-successor verification script, its output, and a claim-status ledger.