41e4d5a0b1
- Introduced new task scheduling system with CancelToken for cooperative cancellation, replacing Rayon-based work scheduling with libuv thread pool integration. - Added Cancellable interface with timeoutMs and signal properties for unified timeout and abort signal handling across all async operations. - Converted async functions (clipboard, html, image, shell, grep, glob) to synchronous functions returning task::Async wrappers for consistent cancellation semantics. - Removed abortShellExecution() function and executionId tracking in favor of centralized CancelToken-based cancellation. - Simplified htmlToMarkdown() signature by removing RequestOptions parameter and delegating cancellation to Cancellable interface.