chore: change license to GPLv2 or later

[GaryJones]

Summary

This PR changes the license from GPL-3.0 back to GPLv2 or later, which is the standard license for WordPress plugins and ensures compatibility with WordPress core.

Background

In PR #727 (commit 8c6193d, May 2024), the plugin header in edit_flow.php was changed from the original GPLv2-or-later license to GPL-3. This was released in version 0.9.9.

However, 0.9.9 shipped with inconsistent license declarations:

• edit_flow.php header: License: GPL-3
• composer.json: GPL-2.0+ (still the old value)
• package.json: GPL-2.0+ (still the old value)
• No LICENSE file existed

After the 0.9.9 release, commit 22551d3 (June 6, 2024) attempted to make the licensing consistent by adding a GPL-3 LICENSE file and updating composer.json and package.json to GPL-3. However, this was never included in a tagged release.

Why This Matters

GPLv3 code is fundamentally incompatible with GPLv2-only code. It is not legally possible to combine code from the two in a single program and redistribute it without violating one of the licenses' terms. That means that someone using a strictly GPLv2-only plugin can't use a GPLv3-only plugin in the same site.

Changes

This PR updates all license references to GPLv2 or later:

• edit_flow.php: Changed plugin header to License: GPLv2 or later
• LICENSE: Replaced GPL-3 text with GPL-2 text
• composer.json: Changed to GPL-2.0-or-later
• package.json: Changed to GPL-2.0-or-later
• package-lock.json: Changed to GPL-2.0-or-later

Contributor Approval

To relicense the contributions made since the GPL-3 change was introduced, we need approval from contributors. Please leave a comment to confirm you're happy for your contributions to be used under "GPLv2 or later":

• @GaryJones
• @alecgeatches
• @ingeniumed
• @hanifn

(Note: dependabot contributions are automated dependency updates and don't require approval)

Test plan

• Verify all GPL-3 references have been removed
• Obtain contributor approvals

Fixes #762 since #727 never added a valid string.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR reverts the license from GPL-3.0 back to GPLv2-or-later across all project files to ensure compatibility with WordPress core, which is licensed under GPLv2. The change addresses an inconsistency introduced in version 0.9.9 where the plugin header declared GPL-3, which is incompatible with GPLv2-only code.

Key changes:

• Standardizes all license declarations to GPLv2-or-later using appropriate identifiers for each file type
• Replaces the GPL-3 LICENSE file with GPL-2 license text
• Ensures consistency across PHP plugin header, composer.json, package.json, and package-lock.json

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
edit_flow.php	Updated plugin header from "GPL-3" to "GPLv2 or later" and changed license URI to GPL-2.0
composer.json	Changed license identifier from "GPL-3.0+" to "GPL-2.0-or-later" using SPDX format
package.json	Changed license identifier from "GPL-3.0-or-later" to "GPL-2.0-or-later"
package-lock.json	Updated license identifier to "GPL-2.0-or-later" throughout the lockfile
LICENSE	Replaced full GPL-3 license text with GPL-2 license text

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[alecgeatches]

@GaryJones Good catch on the inconsistency! I've checked my name off of the list above. Thank you for addressing this.

[ingeniumed]

@GaryJones - Thanks for catching this! I've checked my name off the list above

[GaryJones]

Since the contributions from Hanif were made when he was an Automattician, and Automattic owns all work product created by the employees, no explicit permission is needed to change the license.