Rig Mars Cat from the GLB reference with img2threejs 1.5.2

[jaybmcv]

Summary

• upgrades Mars Cat's generator record to img2threejs 1.5.2
• binds the procedural meshes to the reference GLB's single 95-joint skin in authoritative skin[0].joints order
• runs the 1.5.2 Stage R2 proximity-conditioning pass and repairs the source GLB's measured shorts-pocket-to-thumb.02.R misweight
• adds two conservative authored clips: small-periodic-spine-tail-cycle and right-arm-oscillation
• adds a separately frozen low/game tier: 202,082 vertices and 406,452 triangles, 90.39% fewer triangles than the 4,227,404-triangle fidelity tier

The reference is rigged but contains zero animation clips, so the motions are authored rather than claimed as source-matched. The pocket defect originated in the source skin: 3,268 of 8,013 source-region vertices carried thumb.02.R weight. The repair removes that influence only from the measured pocket vertices and transfers the nearest main-shorts binding. An experimental leg cycle remains rejected because its visual sweep showed shoe/short seam openings.

Verification

• npm run build
• no tracked .glb/.bin and zero runtime .glb/.bin requests
• fidelity mesh parity: 20/20 meshes pass; 0 frozen-buffer differences; only 40 legal skin attributes added
• game mesh parity: 19/19 meshes pass; 0 frozen-buffer differences; only 38 legal skin attributes added
• compact binding: 202,082 game-tier vertices, 0 weight-normalisation failures, maximum joint index 93 of 94
• rig gates G1-G12 evaluated and pass on the game tier; maximum sampled binding delta 2.963e-8 (limit 2^-23)
• game visual sweep: 32 frames; background-through-split pixels 5,024 baseline -> 4,871 animated; crease pixels 74,464 -> 74,406
• browser: 19/19 low-tier visible meshes skinned, two clips, zero .glb/.bin requests