Public Python API - `get_project_snapshot()` and integration tests

[ravi-kumar-pilla]

Description

Expose the public-facing Python API: get_project_snapshot() in kedro/inspection/__init__.py with __all__ exports and optional pipeline_id filtering. Validate the full end-to-end flow with integration tests against the starter project.

Context

This ticket delivers the API surface that plugin authors and platform teams call directly.

Scope

kedro/inspection/__init__.py:

def get_project_snapshot(
    project_path: str | Path,
    env: str | None = None,
    pipeline_id: str | None = None,
) -> ProjectSnapshot:
    """Primary entry point. Returns a full ProjectSnapshot of the project.
    If pipeline_id is set, returns a snapshot scoped to that pipeline only.
    """

def _filter_pipeline(snapshot: ProjectSnapshot, pipeline_id: str) -> ProjectSnapshot:
    """Return a new snapshot containing only the requested pipeline and its datasets."""

__all__ = [
    "get_project_snapshot",
    "ProjectSnapshot",
    "PipelineSnapshot",
    "NodeSnapshot",
    "DatasetSnapshot",
    "ProjectMetadataSnapshot",
]

tests/inspection/test_integration.py (against spaceflights-pandas starter):

• get_project_snapshot() returns a ProjectSnapshot
• snapshot.metadata.project_name and package_name are correct
• At least one pipeline is present with nodes
• snapshot.datasets contains expected catalog entries with correct type and filepath
• snapshot.parameter_keys contains expected keys without values
• pipeline_id filtering returns only the requested pipeline
• Datasets in the filtered snapshot only include those referenced by the requested pipeline's nodes
• json.dumps(dataclasses.asdict(snapshot)) produces valid JSON

Deliverable

• kedro/inspection/__init__.py (final public API)
• tests/inspection/test_integration.py