Explore custom 2D UI drawing on compositor layers via scripting (Slint)

[staging-devin-ai-integration]

Summary

Investigate adding support for custom 2D UI drawing on compositor layers, ideally driven by a scripting or declarative UI language.

Motivation

Enabling custom 2D UI overlays on compositor layers would unlock a wide range of use cases — from HUDs and status panels to interactive controls rendered directly within the media pipeline. Using a declarative UI approach would make this accessible without requiring deep graphics programming knowledge.

Direction to Explore

• Slint as a candidate UI toolkit — it's a declarative UI framework with a domain-specific language, Rust-native, and designed for embedded/resource-constrained targets which aligns well with compositor layer rendering.
• How Slint's rendering backend could integrate with StreamKit's compositor.
• Whether scripting/hot-reload of UI definitions is feasible.
• Performance characteristics for real-time overlay rendering.

Scope

This is a high-level roadmap item for investigation and design. No implementation is expected initially — the goal is to evaluate feasibility and sketch out an architecture.