Add domain blocklist importer

[obenland]

Fixes #2474

Proposed changes:

• Add Blocklist importer class for bulk importing domain blocklists
• Add add_site_blocks() bulk method to Moderation class for efficient imports
• Support Mastodon CSV format (#domain header) and simple domain-per-line text files
• Add quick-import button for IFTAS DNI list
• Add 17 unit tests for CSV parsing

Other information:

• Have you written new tests for your changes, if applicable?

Testing instructions:

• Go to Tools → Import → Domain Blocklist
• Test file upload with a CSV or TXT file containing domain names
• Test URL import by entering a blocklist URL or clicking "Import IFTAS DNI List"
• Verify the import complete message shows correct counts
• Verify blocked domains appear in Settings → ActivityPub → Settings
• Run npm run env-test -- --filter Test_Blocklist

Changelog entry

• Automatically create a changelog entry from the details below.

Changelog Entry Details

Significance

• Patch
• Minor
• Major

Type

• Added - for new features
• Changed - for changes in existing functionality
• Deprecated - for soon-to-be removed features
• Removed - for now removed features
• Fixed - for any bug fixes
• Security - in case of vulnerabilities

Message

Add domain blocklist importer for bulk importing blocked domains.

[Copilot]

Pull request overview

This PR adds a domain blocklist importer feature to enable bulk importing of blocked domains from external sources. It supports multiple formats including Mastodon CSV exports and simple domain-per-line text files, with a quick-import button for the IFTAS DNI list.

Key Changes:

• New Blocklist importer class with CSV parsing and URL import capabilities
• Bulk add_site_blocks() method in Moderation class for efficient batch imports
• Import UI with file upload and URL import options, including IFTAS DNI quick-import

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
includes/wp-admin/import/class-blocklist.php	Core importer implementation with CSV parsing, file upload, and URL import functionality
includes/class-moderation.php	Added bulk add_site_blocks() method for efficient batch domain blocking
includes/wp-admin/import/load.php	Registered the blocklist importer in WordPress import system
tests/phpunit/tests/includes/wp-admin/import/class-test-blocklist.php	Comprehensive test suite with 17 tests for CSV parsing edge cases
.github/changelog/2589-from-description	Changelog entry for the new feature

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[pfefferle]

If I use an email like identifier for a domain, instead of ignoring it, the script fails completely. is @ a reserved divider in CSV?

[obenland]

If I use an email like identifier for a domain, instead of ignoring it, the script fails completely. is @ a reserved divider in CSV?

Can you help me understand where you use that? I've not been able to get beyond this:

[pfefferle]

When you use an email as domain in a CSV!

is @ a reserved divider in CSV?

[obenland]

Hm, I'm unable to reproduce that. e5659cd added tests for it that succeed, too.