chore: pylint and black - CZ conditional

[paulQM]

Fix pylint issues in CZ conditional phase calibration

Summary

This PR fixes all pylint issues in the CZ conditional phase calibration node and its utility modules, bringing the code quality score to 10.00/10.

Changes Made

Main Calibration File

calibrations/CZ_calibration_fixed_couplers/20_cz_conditional_phase.py

• ✅ Added module docstring describing the CZ conditional phase calibration
• ✅ Fixed import order: moved third-party imports before first-party imports (PEP 8 compliance)
• ✅ Added missing function docstrings:
  • custom_param() function
  • save_results() function
• ✅ Removed unused import: from quam.core import operation
• ✅ Added pylint disable comment for too-many-statements in create_qua_program() (function performs cohesive task)

Utility Modules

calibration_utils/cz_conditional_phase/__init__.py

• ✅ Added module docstring describing the CZ conditional phase calibration utilities

calibration_utils/cz_conditional_phase/analysis.py

• ✅ Added module docstring describing analysis functions
• ✅ Added missing function docstring for fit_routine()

calibration_utils/cz_conditional_phase/parameters.py

• ✅ Added module docstring describing parameter definitions
• ✅ Added class docstring for NodeSpecificParameters
• ✅ Added class docstring for Parameters

calibration_utils/cz_conditional_phase/plotting.py

• ✅ Added module docstring describing plotting functions
• ✅ Fixed import order: moved third-party imports (matplotlib, numpy, xarray, qualibration_libs) before first-party imports

Pylint Results

• Before: 8.75/10 (main file), 9.34/10 (utility files)
• After: 10.00/10 (all files)

Testing

• ✅ All files pass pylint with perfect score
• ✅ No functional changes - only code quality improvements
• ✅ Import order follows PEP 8 guidelines

Impact

• Improves code maintainability and readability
• Ensures compliance with project linting standards
• No breaking changes to functionality