Metric Domains and Branch Gates in a Scenario-First Coherent-Affine Framework

We formulate a scenario-first selected-branch coherent-affine substrate framework. The aim is not to derive a completed meta-functional over all possible branches, but to define a disciplined effective-branch setting in which metric structure, relational clocks and physical readouts are introduced only after a controlled scenario has been specified. A physical scenario consists of an exterior spacetime or effective exterior theory, a candidate locking surface, an interior branch, a clock and metric domain, an external readout map and a validation protocol. This ordering is the central methodological point: numerical readouts cannot carry evidential weight before the domain in which time, metric structure and observables are meaningful has been fixed