Write unit tests for IntentGraph builder

[Nehal-cell]

What

The IntentGraph builder currently has no unit tests. Add tests that verify correct intent classification for common Python patterns.

Test cases to cover

• Simple Flask route handler → classified as request_handler
• Pandas DataFrame transform function → classified as data_transformer
• Class with __init__ and DB calls → classified as data_model
• Utility function with no framework imports → classified as helper

Files

• tests/test_intent_graph.py (create new)