Align pi0.7 minimal structure with paper

tests/test_data.py

@@ -76,7 +76,6 @@ def test_policy_variants_and_metadata() -> None:
         "quality": 5,
         "mistake": False,
         "control_mode": "ee",
-        "source_type": "demonstration",
     }
     assert torch.allclose(policies[-1].future_xy[-1], policies[-1].future_xy[4])
 
@@ -105,12 +104,13 @@ def test_dataset_contract_and_roundtrip(tmp_path: Path) -> None:
     assert item["history_states"].shape == (6, 2)
     assert item["current_state"].shape == (2,)
     assert item["actions"].shape == (16, 2)
-    assert item["subgoal_heatmap"].shape == (1, 32, 32)
+    assert item["future_observation"].shape == (3, 32, 32)
     assert item["subgoal_pixel_values"].shape == (3, 32, 32)
     assert item["ambiguous_history_pair"].shape == (2, 6, 2)
     assert 0 <= item["rtc_delay_steps"] <= 12
-    assert item["rtc_target_actions"].shape == (16, 2)
-    assert item["rtc_valid_mask"].shape == (16,)
+    assert item["rtc_action_prefix"].shape == (16, 2)
+    assert item["rtc_prefix_mask"].shape == (16,)
+    assert item["rtc_postfix_mask"].shape == (16,)
     assert item["reasoning"] == "Steer left."
     assert item["prompt_component_mask"].all()
     assert item["token_metadata"]["quality"] == 5
@@ -131,4 +131,4 @@ def test_dataset_is_deterministic_per_index(tmp_path: Path) -> None:
     second = dataset[3]
     assert first["prompt_components"] == second["prompt_components"]
     assert first["rtc_delay_steps"] == second["rtc_delay_steps"]
-    torch.testing.assert_close(first["rtc_target_actions"], second["rtc_target_actions"])
+    torch.testing.assert_close(first["rtc_action_prefix"], second["rtc_action_prefix"])