contour-to-meshlisted

# Contour to Mesh Use this when a reference silhouette is the contract. The mesh starts as a filled 2D contour in front-view X/Z, then gets shallow Y depth/crown after validation. ## Workflow 1. Extract or select a clean contour/mask for one structural part. 2. Generate a triangulated mesh recipe with `scripts/mask_to_mesh_recipe.py`. 3. Run the generated Blender Python to create a named `GEO_*` mesh. 4. Assign front-projected UVs immediately. 5. Add depth only as a modifier or vertex displacement that preserves X/Z boundary positions. 6. Validate the front render against the source mask. ## Hard rules - Do not use radial duplication unless the manifest says the source is symmetric. - Do not use a generic ellipse if a contour exists. - Boundary vertices must keep source X/Z coordinates. - Depth deformation may move Y and inner vertices, but must not alter front silhouette. - One structural source part should become one named structural mesh. ## Blender pattern Generated mesh coordinates should map image `x` to Blender `X` and image `y` to Blender `Z` with vertical flip. Use `Y` only for thickness/depth. ## Front-plane rotation rule In this Blender coordinate convention, the front camera looks along the Y axis and the reference silhouette lives in the X/Z plane. Therefore 2D rotations inside the front view are rotations around the **Y axis**, not around Z. Use `rotation_euler = (0, angle, 0)` for 2D component orientation in the front projection. Z rotation spins obje