fix: preserve graph types and metadata in sorting and splitting utilities

[AdMub]

Describe your changes

This PR fixes a silent data-loss bug in the core networkx_utils functions: sort_nodes_internally and sort_nodes_in_graph.

Previously, these functions hardcoded the output as a standard networkx.DiGraph(). This meant that if a user passed in a different graph type (e.g., an undirected Graph or a MultiDiGraph), or if the graph contained critical global metadata (such as coordinate reference systems graph['crs'] or mesh spacing graph['dx']), that data was completely stripped and lost during the sort operation.

Changes:

• Replaced hardcoded networkx.DiGraph() with dynamic typing (type(graph)()) to preserve the original graph's class.
• Added graph.update(input.graph) to ensure all top-level graph attributes are safely carried over to the newly returned graphs.

Issue Link

N/A - This addresses a silent bug found during codebase review.

Type of change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📖 Documentation (Addition or improvements to documentation)

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[AdMub]

Hi @mllam, I've resolved the linting failures and all CI checks are now passing. This fix ensures that graph-level metadata (like CRS) is preserved during sorting and splitting. Ready for your feedback!