Kepler Rotation Catalog Yields No Confirmed Stellar J-Harvesting Signals After Eight Filters

The study bins Kepler stars by color and surface gravity, then flags objects rotating more than 4 sigma slower than their peers. Two candidates emerge but are rejected after Gaia DR3 astrometry reveals unresolved companions and WISE photometry shows no anomalous infrared properties. The search framework itself is the advance: it links measurable stellar spin-down directly to potential engineered extraction without requiring mid-infrared excess. Existing Dyson-sphere searches have focused on waste heat; this work demonstrates that rotation catalogs already contain testable predictions for angular-momentum harvesting. The method therefore bridges classical SETI with precision stellar astrophysics, a connection prior technosignature papers largely omitted. No detection is claimed. The pilot upper limit of f_SJH < 4.5e-4 is conservative and rests on the assumption that strong harvesting would produce outliers exceeding the 4-sigma threshold. Follow-up spectroscopy and high-resolution imaging of the two rejected stars are the immediate next steps.