feat: add get_lineage() to Python client

[psaikaushik]

Summary

Adds the missing get_lineage(node_id, depth) method to the Python client, allowing users to fetch the lineage graph for any node directly from Python without resorting to raw curl calls.

Closes #1798 (Python client portion)

What Changed

Added MarquezClient.get_lineage() that calls GET /api/v1/lineage?nodeId=&depth=.

The method follows the same patterns as existing client methods:

• Input validation (node_id must not be None)
• Uses DEFAULT_DEPTH (20) when depth is not specified
• Returns the parsed JSON response

Usage

from marquez_client import MarquezClient

client = MarquezClient(url='http://localhost:8080')

# Get lineage for a dataset
lineage = client.get_lineage('dataset:my_namespace:my_dataset')

# Get lineage for a job with custom depth
lineage = client.get_lineage('job:my_namespace:my_job', depth=5)

Note

This PR covers the Python client. The Java client portion of #1798 will be a separate PR.

Checklist

• Follows existing client patterns
• Includes docstring with node_id format examples
• Input validation for required parameters
• DCO sign-off included

[psaikaushik]

@wslulciuc , @davidjgoss : Can you please take a look and let me know. thanks!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.18%. Comparing base (180f37b) to head (2a159bf).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #3104   +/-   ##
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  Coverage     81.18%   81.18%           
  Complexity     1506     1506           
=========================================
  Files           268      268           
  Lines          7356     7356           
  Branches        325      325           
=========================================
  Hits           5972     5972           
  Misses         1226     1226           
  Partials        158      158           

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