Mythic Masters: beast round 3 on the 40 untouched beasts, and fix slab-like limb thighs #3093

Split from #3085 (its merge/rebuild/commit step is already done: #3084 and #3086 merged, and bun run beasts on main reproduces every committed GLB byte for byte; Imugi is at its 3200 budget with feet 0/0, wings 0).

Left to do, part of #3071:

• Round 3: add detail parts to the 40 beasts no round has touched yet, then score and rescore (see Mythic Masters: recurring beast detail round (score, add a part, rescore) #2854).
• Fix the limb part so thighs stop reading as slabs. Judges flagged Yule Cat, Hidebehind, Leshy and Hodag.

Check each change with bun run beasts and confirm feet and wing counts and the Imugi budget don't move.