debug: instrument VAE load with full traceback

web/app.py

@@ -66,17 +66,25 @@ print(f"Model loaded and JIT-compiled. Grid: {NU}x{NU}")
 
 # Load VAE model for diversity sampling
 VAE_PATH = os.path.join(ROOT, "data", f"variational_formfinder_variational_{TASK}.eqx")
+print(f"[VAE] attempting load from {VAE_PATH}")
+print(f"[VAE] file exists: {os.path.exists(VAE_PATH)}")
 vae_model = None
 if os.path.exists(VAE_PATH):
     try:
         vae_cfg_path = os.path.join(ROOT, "scripts", f"variational_{TASK}.yml")
+        print(f"[VAE] config path: {vae_cfg_path}, exists: {os.path.exists(vae_cfg_path)}")
         with open(vae_cfg_path) as f:
             vae_cfg = yaml.load(f, Loader=yaml.FullLoader)
+        print("[VAE] config loaded")
         vae_skeleton = build_neural_model("variational_formfinder", vae_cfg, gen, mk)
+        print("[VAE] skeleton built")
         vae_model = load_model(VAE_PATH, vae_skeleton)
-        print("VAE model loaded for diversity sampling.")
+        print("[VAE] VAE model loaded for diversity sampling.")
     except Exception as e:
-        print(f"VAE not loaded: {e}")
+        import traceback
+        print(f"[VAE][ERROR] VAE not loaded: {type(e).__name__}: {e}")
+        print("[VAE][TRACEBACK]")
+        traceback.print_exc()
 
 # Static topology (edges, boundary vertices, faces) - sent once
 EDGES = np.array(list(mesh.edges())).tolist()