Fix handling PHP version from Jetpack backup meta file

[wojtekn]

Related issues

• Fixes https://github.com/Automattic/dotcom-forge/issues/10577

Proposed Changes

Recently, Jetpack Backup files started including correct meta.json. It looks like Studio doesn't validate the PHP version correctly, so user who imports such site gets an error.

I propose to add PHP version detection support for Jetpack backups. When importing a Jetpack backup, Studio will now properly detect and use the PHP version from the backup's meta.json file, falling back to the default PHP version if the detected version is not supported.

Changes

• Added PHP version parsing to JetpackImporter
• Refactored PHP version parsing into a shared method
• Added validation against supported PHP versions
• Updated meta file parsing to match Jetpack backup format

Testing Instructions

1. Create a Jetpack backup from a site running PHP 8.1
2. Import the backup into Studio
3. Verify that:
   • The site is created with PHP 8.1
   • If you import a backup with an unsupported PHP version (e.g., 8.5), it falls back to the default version
   • The WordPress version is correctly detected from the backup

You can find a sample meta.json structure in a Jetpack backup:

{
"wordpressVersion": "6.7.2",
"phpVersion": "8.1.31",
"siteUrl": "http://example.com",
"plugins": [...],
"themes": [...]
}

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[ivan-ottinger]

The proposed changes look great.

• I couldn't reproduce the https://github.com/Automattic/dotcom-forge/issues/10577 issue anymore.
• The Jetpack imports are working correctly - setting the PHP version as expected (based on value in meta.json). If the PHP version is not supported, Studio uses the default PHP version.

Thank you for including helpful testing instructions. It made it easier to test.

[ivan-ottinger]

I appreciate moving out the logic into parsePhpVersion. 👌🏼