Make phpMyAdmin work with native PHP runtime

[fredrikekelund]

Related issues

• Fixes RSM-2697

How AI was used in this PR

I used Codex to help me understand how Playground makes phpMyAdmin work. Once I had a 90% understanding and a relatively clear idea of what I thought the Studio implementation should look like, I asked Codex for the implementation, which I then tweaked to simplify.

Proposed Changes

• Make phpMyAdmin work with sites using the native-php runtime.
• This is achieved by copying and slightly modifying DbiMysqli.php and config.inc.php from the Playground repo.
  • The modifications only change where we load files from. With Playground, there's the virtual file system that gives us stable, per-site paths (like /internal/shared/wp-env.php). With the native PHP runtime, we obviously don't have this, so we generate temp files and pass the site-specific paths to the PHP process using environment variables.

Testing Instructions

1. STUDIO_RUNTIME=native-php npm start
2. Have a site that uses the native-php runtime (if you're unsure, just create a new site – it will automatically be assigned this runtime when Studio is run with STUDIO_RUNTIME=native-php)
3. Start that site
4. Click the phpMyAdmin button in the Overview tab in Studio

Pre-merge Checklist

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

[fredrikekelund]

This file is a straight up copy of the Playground source code

[bcotrim]

Works as described
LGTM 👍

[wpmobilebot]

📊 Performance Test Results

Comparing 1941be0 vs trunk

app-size

Metric	trunk	1941be0	Diff	Change
App Size (Mac)	1375.99 MB	1376.01 MB	+0.01 MB	⚪ 0.0%

site-editor

Metric	trunk	1941be0	Diff	Change
load	1575 ms	1501 ms	74 ms	🟢 -4.7%

site-startup

Metric	trunk	1941be0	Diff	Change
siteCreation	8584 ms	8571 ms	13 ms	⚪ 0.0%
siteStartup	4929 ms	4924 ms	5 ms	⚪ 0.0%

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Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)