Use flit-gettext to compile gettext in distributions

[codingjoe]

No description provided.

[Copilot]

Pull Request Overview

This PR migrates the build system from flit_core/flit_scm to flit-gettext with SCM support to enable automatic compilation of gettext translation files during the package build process. The project contains German translations in .po files that need to be compiled.

• Replaces flit_core and flit_scm with flit-gettext[scm] in the build system configuration
• Updates the build backend module path from flit_scm:buildapi to flit_gettext.scm
• Adds gettext system dependency installation to CI and release workflows

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
pyproject.toml	Updates build system requirements and backend to use flit-gettext for translation support
.github/workflows/release.yml	Adds gettext installation step before building release artifacts
.github/workflows/ci.yml	Adds gettext installation step before building distribution packages

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.41%. Comparing base (746ccaa) to head (1c37345).
⚠️ Report is 112 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #166      +/-   ##
==========================================
- Coverage   99.69%   99.41%   -0.29%     
==========================================
  Files          21       21              
  Lines         332      343      +11     
==========================================
+ Hits          331      341      +10     
- Misses          1        2       +1     

Flag	Coverage Δ
python-3.10	93.00% <ø> (?)
python-3.11	93.00% <ø> (?)
python-3.12	93.00% <ø> (?)
python-3.13	93.00% <ø> (?)

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