drop faf_force_estimation/ - redundant snapshot of Sparsh (same protocol, same indenters, smaller subset)

v9: fix channel order. faf_force_estimation unconditional R<->B swap (BGR-stored). sparsh conditional per-image swap (mixed RGB/BGR per Facebook upstream). Refreshed grids

add RGB-vs-BGR comparison grids for sparsh + faf

add sample grids for faf_force_estimation (flat/sharp/sphere)

add Sparsh GelSight (66,444 frames; flat/sharp/sphere indenters) under CC-BY-NC-4.0; I_min=12 + 1.5% bg-diversity filter