Complete-History Selection and Reversible Photonic Loop Histories: A Speculative Global-Viability Framework with a First Residual Test Template

This is a speculative priority and overview note for a proposed complete-history viability framework. The central idea is that local physical laws may define a space of complete lawful histories, while physical realization may require an additional global viability structure. In minimal form, the framework introduces a selector on complete histories, K_min[Φ] = χ_adm[Φ] exp[-Γ C_closure(P_<Φ)], where χ_adm is a hard admissibility filter and C_closure is a soft coarse closure or restart mismatch cost acting on reduced histories. The note distinguishes hard exclusion from soft suppression, emphasizes that ordinary quantum probabilities and local conservation laws are not replaced, and requires any effective cost to respect genuine physical symmetries. Its strongest current explanatory target is the low-entropy beginning and the thermodynamic arrow via restart rarity. The first concrete experimental route proposed here is a reversible photonic loop-history test. Two histories are arranged to have the same final optical state and the same standard optical prediction, but different calibrated internal mode-history cost. In a minimal small-distortion model, the conditional residual scalings are Delta phi_res scales as N eta^2, and 1 - xi_res scales as N^2 eta^4. This note does not claim that the framework is established, that the proposed residual has been observed, or that quantum mechanics is replaced. It is intended as a compact, citable priority statement and as a basis for critical feedback and later development into separate technical papers.