Add Servo + Slint HiDPI rendering demo (#8735)

[AnujayaVijayakumar]

Summary

This PR adds a new example under examples/slint-servo-skeleton that integrates Servo web rendering into a Slint UI using OpenGL.

It serves as a response to issue #8735

What's Included

• A workspace example using two crates: ui/ and web/
• ui/ crate contains Slint-based UI layout and event handling
• web/ crate includes demonstration of embeds Servo
• A bridge that allows Slint to display Servo’s rendered content

Testing

• Built and tested with Rust 1.74 (2024 edition)
• Confirmed correct font scaling at 200% DPI (Windows)
• Runs with cargo run -p ui

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ AnujayaVijayakumar
❌ Anujaya Vijayakumar

---

Anujaya Vijayakumar seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[ogoffart]

Thanks for taking the time to open this PR and contribute to the project.

Unfortunately, this implementation doesn't actually integrate Servo. The example you've provided appears to load an image rather than using Servo for web rendering.
For that reason, we won’t be moving forward with this PR. We appreciate the effort, but for this issue, we're looking for a more direct and functional integration of Servo and Slint.