fix: normalize paths in extracted translation files

[mirekys]

Description

This PR adds a path normalization step to the translation extraction process. When pybabel extracts messages from source code, it includes absolute file paths in the .pot file. This is problematic for shared translation templates because:

1. Absolute paths are machine-specific and break portability
2. They cause unnecessary diffs when different developers run extraction
3. They expose local filesystem structure

The fix adds a _normalize_paths() method that replaces absolute paths with relative paths by stripping the project path prefix from all file references in the .pot file. This ensures consistent, portable translation templates.

Checklist

Ticks in all boxes and 🟢 on all GitHub actions status checks are required to merge:

• I'm aware of the code of conduct.
• I've created logical separate commits and followed the commit message format.
• I've added relevant test cases.
• I've added relevant documentation.
• I've marked translation strings.
• I've identified the copyright holder(s) and updated copyright headers for touched files (>15 lines contributions).
• I've NOT included third-party code (copy/pasted source code or new dependencies).
  • If you have added third-party code (copy/pasted or new dependencies), please reach out to an architect on Discord.

Frontend

• I've followed the CSS/JS and React guidelines.
• I've followed the web accessibility guidelines.
• I've followed the user interface guidelines.

Reminder

By using GitHub, you have already agreed to the GitHub's Terms of Service including that:

1. You license your contribution under the same terms as the current repository's license.
2. You agree that you have the right to license your contribution under the current repository's license.