[szibis]

Changing a light studio backdrop to a dark or saturated color can leave a pale fringe at fractional-alpha boundaries. Add optional local inverse-compositing evidence that replaces only a supported edge pixel’s estimated old backdrop contribution. Existing default recoloring remains unchanged.

Expose prepare_studio_edge_correction for reusable browser/CPU evidence maps and edge_mode="local_unmix" for direct recoloring. Require nearby smooth backdrop samples, plausible foreground recovery and agreement with an opaque anchor; cap channel correction. Preserve alpha, opaque RGB and existing zero-alpha shading. Unsupported fine edges and glass retain explicit uncertainty rather than aggressive cleanup.

Include a generic reproducible comparison board, receipts, API/README documentation and edge/refusal regressions. Known synthetic mixtures improve maximum channel error from47→1 on dark and43→1 on saturated backdrops; independent Node replay matches Python. This does not establish complete halo removal or real-glass fidelity.

Validation:52 focused tests passed; fresh full run2216 passed,19 skipped,306 subtests. No private images, paths, weights or application-specific requirements included. Model inference was not repeated for this CPU-only change.