chore: add echo with precommit compliant

[Kyung-hoon-Jung0]

Summary

This PR focuses solely on pre-commit (pylint/black) compliance for the T2 echo calibration files.

• No functional or behavioral changes
• Added missing docstrings for modules, classes, and functions
• Fixed import order, line length, and code style issues
• Goal: ensure clean pre-commit passes

---

File-by-file summary of changes (non-functional only)

calibration_utils/T2echo/__init__.py

• Added module docstring: "T2 echo experiment utilities for qubit coherence characterization."

calibration_utils/T2echo/analysis.py

• Added module docstring: "Analysis utilities for T2 echo experiment: fitting exponential decay to measure T2 coherence."
• Added function docstring for process_raw_dataset (line 55): "Convert IQ data to voltage if state discrimination is not used."
• Updated class docstring for FitParameters (line 14): Changed from "qubit spectroscopy" to "T2 echo experiment" for accuracy
• Updated function docstring for fit_raw_data (line 62): Changed from "qubit frequency and FWHM" to "T2 echo decay time" for accuracy
• Fixed long lines in commented code (lines 42-43):
  • Split s_saturation and s_x180 strings to comply with line length limits

calibration_utils/T2echo/parameters.py

• Added module docstring: "Parameter definitions for T2 echo experiment."
• Added class docstring for NodeSpecificParameters (line 7): "T2 echo specific parameters for averaging."
• Added class docstring for Parameters (line 18): "Combined parameters for T2 echo calibration node."

calibration_utils/T2echo/plotting.py

• Added module docstring: "Plotting utilities for T2 echo experiment visualizations."
• Replaced dict() call with dict literal {} (line 95)
  • Changed bbox=dict(facecolor="white", alpha=0.5) to bbox={"facecolor": "white", "alpha": 0.5}
• Updated function docstring for plot_raw_data_with_fit (line 15): Changed from "resonator spectroscopy amplitude" to "T2 echo decay" for accuracy

calibrations/1Q_calibrations/06b_echo.py

• Added module docstring: "T2 echo calibration for measuring qubit coherence time." (line 1)
• Fixed import order (lines 1-7):
  • Moved from dataclasses import asdict to standard library import section (before third-party imports)
• Fixed long docstrings by splitting lines (lines 154, 192):
  • execute_qua_program: Split into two lines
  • analyse_data: Split into two lines
• Added function docstring for custom_param (line 51): "Allow the user to locally set the node parameters."
• Added function docstring for save_results (line 231): "Save all node results and state updates."

[sebastianorbell-qm]

All ok!