Route B, Steps 1--6

Single import point for the audited finite-dimensional perturbation layer.

The imported development contains:

• finite avoidance of null sets;
• the movable parameter space and exact frozen-coordinate reconstruction;
• finite mixed-face incidence cases;
• the scalar fixed-witness calculation;
• the canonical selected p-vector coordinate split;
• measurability and full nullity of every existential mixed-face bad set;
• selection of a small endpoint-relative perturbation satisfying direct positive-ray general position, under the explicit origin-margin, frozen-support safety, and facet-neighborhood inputs.