CoreLumen Stage I : Observational Constitution of the Response Framework

This document constitutes Stage I of the CoreLumen Stage Series (v1.0).

Stage I establishes the observational base contract of the CoreLumen program.
It defines the minimal mapping between the phase-dynamics framework with
dynamical vacuum sequestering and cosmological observables.

The Structural Charter v1.0 is enforced:
c_T = 1, c_s^2 > 0, Z_theta > 0.
No additional tensor degrees of freedom are introduced.

Vacuum sequestering removes spacetime-constant vacuum contributions only.
All results are presented within an effective-field-theory regime.
No UV completion is claimed.