carry_overlap_through_anchor lets a scene keep the previous scene's latent
tail for background/environment continuity even when it switches to its own
i2v anchor, instead of the current hard cut. The anchor's own leading frame
stays untouched; only the frames after it carry the old tail.
Also fixes a real gap found along the way: the mixed-anchor branch never
called _apply_configured_guides, so Best-FaceID identity_transfer could
never resolve an identity_pin on an anchor-swap scene — exactly where it's
most useful. Added a standalone lookup so it resolves there too.
digital-garbage
0c46f1f02e