move GraphNodeType to nodes

Signed-off-by: Sajid Alam <sajid_alam@mckinsey.com>

package/kedro_viz/models/flowchart/modular_pipelines.py

@@ -1,6 +1,6 @@
 from pydantic import BaseModel, Field
 from typing import Set, Optional
-from .enums import GraphNodeType
+from .nodes import GraphNodeType
 
 
 class ModularPipelineChild(BaseModel):

package/kedro_viz/models/flowchart/nodes.py

@@ -1,4 +1,5 @@
 from abc import ABC
+from enum import Enum
 from pydantic import (
     BaseModel,
     Field,
@@ -26,14 +27,22 @@
     from kedro.io.core import AbstractDataSet as AbstractDataset  # type: ignore
 
 from .entities import NamedEntity
-from .enums import GraphNodeType
 from .utils import _parse_filepath, _extract_wrapped_func, get_dataset_type
 from kedro_viz.utils import TRANSCODING_SEPARATOR, _strip_transcoding
 from .modular_pipelines import ModularPipelineChild
 
 logger = logging.getLogger(__name__)
 
 
+class GraphNodeType(str, Enum):
+    """Represent all possible node types in the graph representation of a Kedro pipeline."""
+
+    TASK = "task"
+    DATA = "data"
+    PARAMETERS = "parameters"
+    MODULAR_PIPELINE = "modularPipeline"  # CamelCase for frontend compatibility
+
+
 class GraphNode(BaseModel, ABC):
     """Abstract base class representing a node in the graph."""