Add SVN Checker Admin Page

[ernilambar]

Fixes #1434

Summary

• Create SVN Checker admin menu page
• Implement AJAX handler for plugin slug checks
• Add JavaScript for asynchronous report rendering
• Add CSS for checker UI and status badges
• Add PHP unit tests for the changes

Screenshot

[github-actions]

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Co-authored-by: ernilambar <nilambar@git.wordpress.org>
Co-authored-by: frantorres <frantorres@git.wordpress.org>
Co-authored-by: davidperezgar <davidperez@git.wordpress.org>

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[davidperezgar]

Thanks @ernilambar for the tool. I see it's very useful.

Thanks to Codex’s review, I found a false positive for valid repositories using Stable tag: trunk.

The checker treats trunk as a release tag and checks tags/trunk/, then compares the literal value trunk with the plugin version. This produces failures for a valid WordPress.org configuration.

Could we skip the tag-directory section and stable-tag/version comparison when Stable tag is trunk, and add a regression test?

[ernilambar]

@davidperezgar PR has been updated.

[davidperezgar]

I'd change to Plugin Check SVN. It won't break the line in the menu. When you go to the page, it can be named SVN Checker.