fix: enforce asset naming convention

README.md

@@ -72,6 +72,16 @@ Access the app at `http://localhost:3000`
 > Opacity helper textures can be named `opacity.png` for the whole model or `opacity_part-name.png` to target a mesh/material whose name contains `part-name`; alpha-channel PNGs are converted to alpha maps for the preview.
 > If `model.gltf` references a missing `.bin` but the folder contains exactly one other `.bin`, the preview can use it as a local fallback and shows a warning because the final upload may still be broken until the `.bin` filename matches the GLTF reference.
 
+### Asset naming convention
+
+Texture filenames must start with a known asset family. Use `asset.png` to apply a texture to the whole model, or `asset_object.png` to target a specific object.
+
+Allowed families are defined in `lib/asset-naming.ts`: `baseColor`, `color`, `roughness`, `normal`, `normalOpengl`, `metallic`, `metalness`, `occlusionRoughnessMetallic`, `height`, `opacity`.
+
+Valid examples: `color.png`, `baseColor_lampe.png`, `normalOpengl_cable1.png`, `opacity_lampe.png`.
+
+Invalid examples: `lampe_opacity.png`, `cable1_base_color.png`, `normal_opengl_cable1.png`. Invalid or unknown asset names block the upload.
+
 ### Production (Coolify / Docker)
 
 ```bash
@@ -238,6 +248,7 @@ lib/
 ├── upload-staging.ts      # Temporary server-side staging and prepared asset reuse
 ├── upload-lock.ts         # Lightweight in-memory per-folder upload lock
 ├── asset-classification.ts # Group assets by family for commit messages
+├── asset-naming.ts       # Allowed asset families and naming convention helpers
 ├── commit-message.ts      # Commit message builder
 ├── parse-upload.ts        # FormData parser + validation
 ├── validate-folder.ts     # Client-side folder validation (discriminated union)