X72-53: Floquet Rescue-Cascade Tail Asymptotics

Building on Round 52's conclusion that 'a rescue must export source debt upward,' this round establishes the asymptotic law for source transfer of general hidden blocks at large sideband depth, derives the frozen characteristic polynomial of the one-sided rescue recursion, and proves that its asymptotic solutions split exactly into three branches: a growing branch, an alternating branch, and a minimal branch. Proves that for the typical one-sided central rescue recursion, on both source fibers corresponding to the golden ratio the numerics fall into the growing branch rather than the required minimal branch — so if a complete analytic rescue exists, it must rely on global, two-sided hidden degrees of freedom to select the minimal branch exactly, rather than on a purely local cascade. Route halts at STOP-C57 (one-sided factorial blow-up / minimal-branch matching gap), handed to the next round to perform two-sided minimal Floquet matching; this round also includes a numerical-verification script.