[major]: non-Sendable parameters

[tayloraswift]

No description provided.

[gemini-code-assist]

Code Review

This pull request updates JavaScriptModule to support registering asynchronous callbacks that either run on the @MainActor (allowing non-Sendable parameters) or run nonisolated (requiring Sendable parameters). Feedback was provided to ensure that the closure passed to JSClosure.async in the @MainActor registration method is explicitly isolated to @MainActor to prevent compiler warnings or errors under Swift 6 strict concurrency when handling non-Sendable parameters.

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[gemini-code-assist]

Under Swift 6 strict concurrency, passing non-Sendable parameters (each T) across isolation boundaries from a nonisolated context to the @MainActor operation closure will trigger compiler warnings or errors. Since the callback is registered to run on the @MainActor, the closure passed to JSClosure.async should be explicitly isolated to @MainActor as well. This ensures that argument extraction and the subsequent call to operation occur entirely on the main actor, preventing any unsafe crossing of isolation boundaries.

            JSClosure.async { @MainActor in