Preserve external MySQL database names

[atirna]

Related issues

• Fixes Native PHP runtime forces external MySQL database name to wordpress #4672

How AI was used in this PR

Used AI assistance while investigating and implementing this fix. I reviewed and own the patch.

Proposed Changes

• Uses the site's SQLite integration state to decide whether Studio owns DB_NAME.
• Sets DB_NAME to wordpress for SQLite sites, including empty, dynamic, or duplicate definitions.
• Leaves all DB_NAME definitions untouched for external MySQL sites.

Testing Instructions

• npm test -- apps/cli/lib/native-php/tests/site-setup.test.ts (10 passed)
• npx prettier --check apps/cli/lib/native-php/site-setup.ts apps/cli/lib/native-php/tests/site-setup.test.ts apps/cli/lib/import-export/import/importers/importer.ts
• npx eslint apps/cli/lib/native-php/site-setup.ts apps/cli/lib/native-php/tests/site-setup.test.ts apps/cli/lib/import-export/import/importers/importer.ts apps/cli/php/wp-config-transformer.php
• php -l apps/cli/php/wp-config-transformer.php

Pre-merge Checklist

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

[gavande1]

Thank you @atirna for opening this and for digging into the root cause. I have left a few comments inline, mostly around the edge cases for the preserved value.

[gavande1]

Thanks, @atirna, for addressing the feedback. I will take a look shortly.