Mythic Masters: builder detail parts for the beasts (scales, teeth rows, ears, broad feathers, fur rooted on blobs) #2807

Part of #2802 (the detail front), after the builder fixes in #2795. One worker, from main.

The beasts are blob-and-stick shapes because apps/wildclash/blender/beast.py has no parts for the surface. New sheet parts to add to the builder, each with a row in the field list at the top of beast.py and a line in the app README:

• Scales / plates: a row of overlapping flat scales along a chain (rows, spread, overlap), for crocodilian backs, shells and dragon bellies.
• Teeth rows: small cones fanned along the lip of a muzzle node, upper and lower, so an open mouth reads.
• Ears: a flat, cupped leaf on a node with tilt and cup, mirrored with l_ names.
• Broad feathers: feathers on a membrane that have a tip width (today a feather's tip radius is 0, so a row is a sawtooth; see Mythic Masters: builder fixes the second art pass hit (Nessie blend, feather tips, sphinx wings, tufts in blobs) #2795).
• Fur rooted on a blob's surface: a tuft whose root is projected to the blob surface rather than the node radius, so sink guesswork goes away (also in Mythic Masters: builder fixes the second art pass hit (Nessie blend, feather tips, sphinx wings, tufts in blobs) #2795).
• Brows and lips: a short ridge above each eye and along the muzzle, so faces have expression.

Keep the rule: one sheet always builds the same GLB; every sheet's feet come out as rig tips. Try each part on two or three sheets (bun run beasts, judge the contact sheet in blender/out/) and score before and after out of 10 in the PR. The per-region sheet passes that use these parts are #2808.