Refactor: Bun: use FileHandle.writeFile()

[emmercm]

RE: https://github.com/oven-sh/bun/issues/10874

[github-actions[bot]]

:test_tube: Branch testing instructions

This pull request can be tested locally with the following command:

npm exec --yes -- "github:emmercm/igir#emmercm/bun-writefile-refactor" [commands..] [options]

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 93.09%. Comparing base (7f59ca6) to head (12d2d51).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1114 +/- ## ======================================= Coverage 93.09% 93.09% ======================================= Files 97 97 Lines 6211 6211 Branches 1479 1387 -92 ======================================= Hits 5782 5782 - Misses 408 428 +20 + Partials 21 1 -20 ```

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[github-actions[bot]]

:lock: Inactive pull request lock

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.

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