feat: new OBJ files + chaos architecture scene via MCP

New OBJ files:
- pyramid.obj: 4-sided pyramid with CCW winding
- diamond.obj: octahedron (8 faces, CCW)
- torus.obj: donut shape (24x16 segments)
- cone.obj: 24-sector cone with bottom cap

Scene created via MCP (spawn_model with physics):
- 28 sphere pyramid (7 layers, physics)
- 30 falling diamonds (physics)
- 8 floating torus rings (no physics, decorative)
- 4 pyramid decorations (static)
- 4 cone pillars (static)

Content/cone.obj

@@ -0,0 +1,75 @@
+# Cone
+v 0 0.5 0
+v 0.500000 -0.5 0.000000
+v 0.482963 -0.5 0.129410
+v 0.433013 -0.5 0.250000
+v 0.353553 -0.5 0.353553
+v 0.250000 -0.5 0.433013
+v 0.129410 -0.5 0.482963
+v 0.000000 -0.5 0.500000
+v -0.129410 -0.5 0.482963
+v -0.250000 -0.5 0.433013
+v -0.353553 -0.5 0.353553
+v -0.433013 -0.5 0.250000
+v -0.482963 -0.5 0.129410
+v -0.500000 -0.5 0.000000
+v -0.482963 -0.5 -0.129410
+v -0.433013 -0.5 -0.250000
+v -0.353553 -0.5 -0.353553
+v -0.250000 -0.5 -0.433013
+v -0.129410 -0.5 -0.482963
+v -0.000000 -0.5 -0.500000
+v 0.129410 -0.5 -0.482963
+v 0.250000 -0.5 -0.433013
+v 0.353553 -0.5 -0.353553
+v 0.433013 -0.5 -0.250000
+v 0.482963 -0.5 -0.129410
+f 1 3 2
+f 1 4 3
+f 1 5 4
+f 1 6 5
+f 1 7 6
+f 1 8 7
+f 1 9 8
+f 1 10 9
+f 1 11 10
+f 1 12 11
+f 1 13 12
+f 1 14 13
+f 1 15 14
+f 1 16 15
+f 1 17 16
+f 1 18 17
+f 1 19 18
+f 1 20 19
+f 1 21 20
+f 1 22 21
+f 1 23 22
+f 1 24 23
+f 1 25 24
+f 1 2 25
+v 0 -0.5 0
+f 26 2 3
+f 26 3 4
+f 26 4 5
+f 26 5 6
+f 26 6 7
+f 26 7 8
+f 26 8 9
+f 26 9 10
+f 26 10 11
+f 26 11 12
+f 26 12 13
+f 26 13 14
+f 26 14 15
+f 26 15 16
+f 26 16 17
+f 26 17 18
+f 26 18 19
+f 26 19 20
+f 26 20 21
+f 26 21 22
+f 26 22 23
+f 26 23 24
+f 26 24 25
+f 26 25 2