Add warning for when the LLMs.txt cannot be generated in our dashboard.

[thijsoo]

Context

• We want to notify customers when we cannot generate a llms.txt for them.

Summary

This PR can be summarized in the following changelog entry:

• Enhances the UX of the llms.txt feature by informing users about potential issues with generating the file via Yoast's alert center.

Relevant technical choices:

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Remove your llms.txt file if you have it and make sure our feature is disabled.
• Go to our alert center and make sure there are no problems relating to the llms.txt feature.
• Enable the feature and make sure it works.
• Go to our alert center and make sure there are no problems relating to the llms.txt feature.
• Edit your llms.txt file and add a character. This makes it so we no longer control the file.
• Either disable and re-enable the feature or run the cron job to regenerate it.
• Go to our alert center and make sure there is now problem relating to the llms.txt feature. Make sure it looks like what is in the issue.
• Remove the llms.txt file and regenerate it and make sure the alert center is empty again.
• Now add the following filter:

add_filter( 'filesystem_method', 'disable_filesystem_method' );

function disable_filesystem_method( $url ) {
	return false;
}

• Regenerate the file and make sure you see :
  

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Default Block/Gutenberg/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change. For example, comments in the Relevant technical choices, comments in the code, documentation on Confluence / shared Google Drive / Yoast developer portal, or other.

Quality assurance

• I have tested this code to the best of my abilities.
• During testing, I had activated all plugins that Yoast SEO provides integrations for.
• I have added unit tests to verify the code works as intended.
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.
• I have checked that the base branch is correctly set.

Innovation

• No innovation project is applicable for this PR.
• This PR falls under an innovation project. I have attached the innovation label.
• I have added my hours to the WBSO document.

Fixes #

[coveralls]

Pull Request Test Coverage Report for Build 2044bc2a5062d7c6c86817e9cf3cf3ec3cc12b8f

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 10 of 52 (19.23%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall first build on 611-show-warning-in-yoast-dashboard-when-llmstxt-cant-be-created-nice-to-have at 53.106%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/llms-txt/user-interface/file-failure-llms-txt-notification-integration.php	10	27	37.04%
src/llms-txt/application/file/file-failure-notification-presenter.php	0	25	0.0%

Totals
Change from base Build 687a2c1e05a7d3a86cf158fba04e7aef45dcccd3:	53.1%
Covered Lines:	29826
Relevant Lines:	57085

---

💛 - Coveralls

[leonidasmi]

CR: ❌

I think this implementation is blocked by this issue, so let's talk to see what we should do.

[leonidasmi]

It looks like we have a single message that describes only the not_managed_by_yoast_seo case. We need to be able to show the different message when on the filesystem_permissions case.

[leonidasmi]

CR + Acceptance test is ✔️