Reachable Geometry as the Deep Ground of Dynamical Structuralism: A Concept Note v0.1

This concept note establishes Reachable Geometry as the deepest geometric ground of Dynamical Structuralism (DS). The core proposition is that Reachable Geometry is neither created nor destroyed — it is only illuminated or occluded. Symmetry breaking is defined not as the creation of new possibilities, but as the moment when illumination conditions change, making certain geometric paths reachable and others recede. The note includes an image anchor (the moon and its phases), a derivation path distinguishing what symmetry breaking is and is not, and an ontological position statement locating Reachable Geometry as the root from which the entire existing DS architecture (Lake Model, TOM, HÚPLŃ, LIN System) grows. This v0.1 is a priority registration of the proposition and derivation path; full architectural integration will follow as v0.2.