Mythic Masters: beast surfaces, what is still weak after round 3 #3070

Left over from the beast surfaces PR (#3067). A fresh judge scored the gallery 4.5 before and 5.5 after, then stopped moving.

• Dark creatures (Black Shuck, Cadejo, Mothman, Hidebehind, Kelpie, Minotaur) still read as one value: needs per-sheet hue shifts or a lighter secondary colour, not a global lift.
• Materials do not separate: horns, claws, eyes, teeth are tiny; nothing reads as wet, glossy or metal. Try an env-map specular or matcap term on those materials, and bigger sheet parts (lane B).
• No custom or weighted normals yet (Guilty Gear Xrd, Motomura GDC 2015): transfer normals from a smooth proxy so low-poly skin shades smooth.
• Gallery has no "loaded" signal and shots are copied by hand; a gallery-shots CLI or WebMCP tool would make before/after judging repeatable.