Studio: Update Studio scheme protocol handler to AppxManifest for Windows

[gavande1]

Related issues

• Fixes STU-936

Proposed Changes

• Update Studio protocol from from wpcom-local-dev to wp-studio to the existing app manifest

Testing Instructions

Taken from #1969, Props to @bcotrim

1. Download the signed .appx file from the CI build artifacts for this PR (https://buildkite.com/automattic/studio/builds/9170/steps/canvas?jid=019aa14c-6f7d-4be5-bbac-d950b13e7e91)
2. Install the .appx on a Windows machine (right click -> Install)
3. Open Studio and click the "Login" button in the top right
4. Authenticate in the browser when redirected to WordPress.com
5. After approving, verify the browser shows "Authorized. You can now open Studio and close this window."
6. Verify Studio successfully logs you in and displays your account information

Pre-merge Checklist

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

[gavande1]

This needs to be deployed after #2029 is deployed.

[github-actions]

📊 Performance Test Results

Comparing 5acc4ca vs trunk

site-editor

Metric	trunk	5acc4ca	Diff	Change
load	17114.00 ms	14498.00 ms	-2616.00 ms	🟢 -15.3%

site-startup

Metric	trunk	5acc4ca	Diff	Change
siteCreation	27589.00 ms	27352.00 ms	-237.00 ms	🟢 -0.9%
siteStartup	9028.00 ms	11009.00 ms	+1981.00 ms	🔴 21.9%

---

Results are median values from multiple test runs.

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

[gcsecsey]

In #2018 we made builds on PRs optional, so I started the Windows builds on Buildkite for this PR. ⌛

[gavande1]

Thanks @gcsecsey for running the Windows build.

[gcsecsey]

Thanks for updating the handler @gavande1! This works well for me on Windows. 👍

CleanShot.2025-11-20.at.13.32.26.mp4

[gavande1]

I am deploying this for beta release. Feel free to test it again for edge cases.