chore: remove @slack/webhook dependency

[enricobattocchi]

Context

Slack webhook notifications are no longer functional — the webhooks have been decommissioned. The @slack/webhook package and all related Grunt task code are dead code that should be removed.

Summary

This PR can be summarized in the following changelog entry:

• Removes the unused @slack/webhook dependency and the notify-slack Grunt task.

Relevant technical choices:

• Removed the colors/safe import from prompt.js as it became unused after removing the Slack prompt definitions.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Run yarn install — should complete without errors.
• Run grunt build — should complete without errors (no references to removed task).
• Grep the codebase for notify-slack and @slack/webhook — no matches should remain outside of git history.

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.

Impact check

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

• Only the Grunt release pipeline (create-beta, create-rc aliases). No runtime plugin code is affected.

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.
• This PR also affects Yoast SEO for Google Docs. I have added a changelog entry starting with [yoast-doc-extension], added test instructions for Yoast SEO for Google Docs and attached the Google Docs Add-on 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.
• I have run grunt build:images and commited the results, if my PR introduces new images or SVGs.

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.

🤖 Generated with Claude Code

[coveralls]

Coverage Report for CI Build 9

Coverage increased (+0.7%) to 54.152%

Details

• Coverage increased (+0.7%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

---

Coverage Stats

Relevant Lines:	24989
Covered Lines:	13256
Line Coverage:	53.05%
Relevant Branches:	6825
Covered Branches:	3972
Branch Coverage:	58.2%
Branches in Coverage %:	Yes
Coverage Strength:	120376.79 hits per line

---

💛 - Coveralls

[Copilot]

Pull request overview

Removes decommissioned Slack webhook notification plumbing from the Grunt release pipeline, including the @slack/webhook dependency and all notify-slack task configuration, prompts, and environment variables.

Changes:

• Removed @slack/webhook from devDependencies and pruned related entries from yarn.lock.
• Deleted the notify-slack custom Grunt task and its task-config, and removed the task from release aliases and JIT task mappings.
• Removed Slack-related prompt definitions (and the now-unused colors/safe import) plus Slack token entries from .env.example.

Reviewed changes

Copilot reviewed 6 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
yarn.lock	Removes @slack/webhook (and its transitive deps/keys) from the lockfile.
package.json	Drops @slack/webhook from devDependencies.
config/grunt/task-config/prompt.js	Removes Slack-specific prompts and the unused colors/safe import.
config/grunt/task-config/notify-slack.js	Deletes the Slack notification task configuration.
config/grunt/task-config/aliases.yaml	Removes notify-slack:* from create-beta / create-rc alias chains.
config/grunt/custom-tasks/notify-slack.js	Deletes the custom Grunt task implementation that sent Slack webhooks.
Gruntfile.js	Removes the JIT static mapping for the notify-slack task.
.env.example	Removes Slack token env var placeholders.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.