Rename and add demo.py for dataset loading

demo.py

@@ -0,0 +1,36 @@
+import os
+import datasets
+
+class VisionReasonerDataset(datasets.GeneratorBasedBuilder):
+    def _info(self):
+        return datasets.DatasetInfo(
+            features=datasets.Features({
+                "id": datasets.Value("string"),
+                "problem": datasets.Value("string"),
+                "solution": datasets.Value("string"),
+                "image": datasets.Image(),  # Enables image previews
+                "img_height": datasets.Value("int32"),
+            }),
+        )
+
+    def _split_generators(self, dl_manager):
+        parquet_path = os.path.join(dl_manager.manual_dir, "visionreasoner_dataset.parquet")
+        return [
+            datasets.SplitGenerator(
+                name=datasets.Split.TRAIN,
+                gen_kwargs={"filepath": parquet_path}
+            ),
+        ]
+
+    def _generate_examples(self, filepath):
+        import pandas as pd
+        df = pd.read_parquet(filepath)
+        for idx, row in df.iterrows():
+            yield idx, {
+                "id": row["id"],
+                "problem": row["problem"],
+                "solution": row["solution"],
+                "image": row["image"]["path"],
+                "img_height": row["img_height"],
+            }
+