Sync Coast-style multi-scale fusion

configs/dual_dinov3_vit_convnext.json

@@ -13,7 +13,11 @@
     },
     "fusion": {
       "out_channels": 256,
-      "method": "concat_conv_bn_gelu"
+      "method": "coast_style_cross_scale_attention",
+      "semantic_sources": ["vit", "convnext_c4", "convnext_c16", "convnext_c32"],
+      "detail_source": "convnext_c8",
+      "detail_grid_size": [28, 28],
+      "output_features": ["fused", "semantic", "detail", "convnext_pyramid"]
     },
     "normalization_policy": {
       "unfreeze_all_norm": true