Add get_defined_name wrapper for Excelize GetDefinedName

[Siyet]

PR Details

Implement Go export GetDefinedName returning DefinedName list.

Description

• Add Python wrapper File.get_defined_name() to retrieve defined names.
• Go: export GetDefinedName returning a list of excelize.DefinedName.
• C: introduce GetDefinedNameResult to pass arrays across the FFI boundary.
• Python ctypes: add _GetDefinedNameResult in types_go.py and wire lib.GetDefinedName.
• Tests: extend test_defined_name to assert retrieval after setting a defined name.
• Mirrors upstream Excelize behavior and complements existing set_defined_name / delete_defined_name.

Refs: https://github.com/qax-os/excelize/blob/42840b3fd595d3221257af1a596612b9045b25ce/sheet.go#L1828

Related Issue

N/A

Motivation and Context

• Achieve feature parity with Go Excelize’s GetDefinedName.
• Provide a complete defined name lifecycle in Python: set/get/delete.
• Enables introspection and validation of named ranges in user code.

How Has This Been Tested

Unit tests: updated test_defined_name to:

• set a defined name
• call get_defined_name()
• assert the name exists with expected scope

Smoke tested by creating a new workbook and enumerating returned names.

Environment:

• Go 1.23
• Python 3.12.11
• OS: Ubuntu 22.04

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (834d53f) to head (0d5bebd).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #29   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines         2954      2972   +18     
=========================================
+ Hits          2954      2972   +18     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

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[Siyet]

@xuri Thanks for the updates to my PR. Do you need anything else from me before merging it into main?

This is my first contribution to an open-source library. :)

[xuri]

Great work, thanks for your contribution!