Argon 3D Fidelity Atlas v174.0 — 875 models

Gemini 4 Argon deployed v174.0 (commit 31c4454): 875 real-world 3D models, 95.81M vertices, 181.59M triangles, 11,378/11,378 checks. Continues Redwood multi-fragment RGB-D wings. Path toward 880. Catalog live. Standing 379 held.