Améliore le visuel de l'avatar Eve — lissage géométrique et couvertures de jointures

- Fusion de vertices plus agressive (corps 0.08, bras 0.07, tête 0.08)
- Matériau laque blanche unifié : emissiveIntensity 0.16, clearcoat 1.0
- Matériau tête dédié : emissiveIntensity 0.28 pour effacer les ombres aux seams
- Collar élargi (tube 0.14), cylindre de cou ajouté, épaulières agrandies (scale Z 0.56)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/avatars/README.md

@@ -0,0 +1,24 @@
+Place premium avatar assets here.
+
+Expected files:
+
+- `retrobot-space-explorer.glb` for Nova
+- `aegis.glb` for Aegis
+
+The selected Retrobot Space Explorer asset may be distributed as FBX. If so, convert it to GLB before placing it here. Recommended Blender export settings:
+
+- Format: glTF Binary (`.glb`)
+- Include: selected object(s), materials, textures, animations
+- Transform: +Y up / glTF default
+- Compression: optional, only after verifying the model renders correctly
+
+If the file is missing, EveFlow falls back to the existing Eve model.
+
+To activate an installed model, update `avatar-manifest.json` after placing the file here:
+
+```json
+{
+  "nova": "/avatars/retrobot-space-explorer.glb",
+  "aegis": "/avatars/aegis.glb"
+}
+```