Add automated DevTools extensions installation for development

[wojtekn]

Related issues

• Follow up to Replace electron-devtools-installer with native Electron API #2307

Proposed Changes

PR #2307 removed electron-devtools-installer (which used deprecated Electron APIs) and replaced it with native extension loading. However, this removed the automatic download functionality, causing errors for developers cloning the repo fresh.

This PR restores the automatic installation behavior using a custom script that:

• Downloads extensions directly from Chrome Web Store via Google's update service
• Parses CRX file format and extracts extension files
• Installs to the correct user data directory
  Gracefully handles failures (extensions are optional for development)

Testing Instructions

Test with fresh clone (simulating new developer experience):

1. Remove existing extensions if present

rm -rf ~/Library/Application\ Support/Studio/extensions

2. Run the app using npm start
3. Confirm the following:

• extensions should download automatically during prestart
• no errors about missing extensions in the console
• React DevTools and Redux DevTools should be available in DevTools

Test extensions already installed

1. Run command:

npm run setup:devtools

2. Confirm the following:

• should skip download with message "Extension already installed, skipping download"

Test manual installation:

1. Run commands:

rm -rf ~/Library/Application\ Support/Studio/extensions
npm run setup:devtools

2. Confirm the following:

• should download and install both extensions successfully
• verify extensions work:

Pre-merge Checklist

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

[wpmobilebot]

📊 Performance Test Results

Comparing 89a4ef7 vs trunk

site-editor

Metric	trunk	89a4ef7	Diff	Change
load	2918.00 ms	2919.00 ms	+1.00 ms	🔴 0.0%

site-startup

Metric	trunk	89a4ef7	Diff	Change
siteCreation	8102.00 ms	7065.00 ms	-1037.00 ms	🟢 -12.8%
siteStartup	3938.00 ms	3944.00 ms	+6.00 ms	🔴 0.2%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change

[wojtekn]

I'm closing this in favor of #2437