[CI] Cron job workflow to run `test-and-fix` and commit results

[chalin]

We should consider setting up a workflow to execute npm run test-and-fix and commit results, so as to minimize the likelihood of our contributors being told to keep their PRs focused to their own changes, like #6585 (comment). /cc @svrnm

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Edit 2025/06

Here's what I think we need two reusable actions (such as these actions from our repo) to do the each of the following (as separate actions):

• Apply any npm run XXX script (un trusted), and creates a patch files
• A reusable action (trusted), that can create a PR from a patch file

Create another action, or just a script to run test-and-fix, using the two actions previously mentioned.

[chalin]

Actually, as discussed on Slack, let's run the i18n checks on every PR instead.

[svrnm]

Actually, as discussed on Slack, let's run the i18n checks on every PR instead.

agreed, that's the one that makes the most issues