Galaxy rotation curves and weak gravitational lensing are usually interpreted as distinct observational consequences of an unseen dark-matter halo. In the ECSM framework, this paper tests whether both can instead be organised as different observable projections of a common finite-response source relation. Using SPARC rotation-curve data and KiDS-1000 galaxy–galaxy lensing bandpowers, the V4 analysis finds that SPARC favours a dynamical effective exponent near 0.70, while KiDS favours an optical effective exponent near 1.45. A common-source profile relation identifies a joint source exponent near 1.40, with sector-dependent projection factors. The SPARC full radial projection improves over a baryonic velocity baseline by approximately 0.861, while the KiDS fast local common-source model improves over a smooth angular control by approximately 0.793. A SPARC galaxy-held-out validation remains positive, with a fractional improvement of approximately 0.353 and four out of five positive folds. The results do not constitute a final replacement for dark matter, but support a candidate dark-sector response bridge in which rotation-curve excess and weak-lensing excess are organised by a shared finite-response source relation.
Adam Sheldrick (Mon,) studied this question.