…ar deps, and refactor

enhance tool:
- Now actually applies input blocks (input-slider) for hardcoded values like
  test_size, n_estimators, threshold, learning_rate, max_depth
- Modifies code to reference the input variable instead of hardcoded value
- Adds section headers (h1, h2) when structure enhancement is applied

fix tool:
- Implements circular dependency detection using DAG analysis
- Attempts to break cycles by reordering blocks (moving high-output blocks earlier)
- Reports detected cycles with the variables involved

refactor tool:
- Now removes extracted functions/classes from source blocks
- Adds import statements to source notebooks (from <module> import <names>)
- Reports sourceModified and importAdded in response

Updated tool descriptions to accurately reflect new capabilities.