This PR adds comprehensive async function support to BridgeJS, enabling seamless interoperability between Swift async functions and JavaScript Promises.
Swift functions marked with async are now automatically exposed as JavaScript functions returning Promise<T>

Implementation Details

Core Changes

• ExportSwift.swift: Modified to detect async functions and wrap calls with JSPromise.async, handling proper return value conversion
• BridgeJSLink.swift: Updated TypeScript signature generation to emit Promise<T> for async functions
• TypeScript processor: Enhanced to recognize Promise types and generate appropriate bridge types

API Changes

• Import initialization: Changed from imports: {...} to getImports() { return {...} } pattern to allow accessing exports inside imports implementation.

Example Usage

Swift side:

@JS func fetchUserData(_ userId: String) async -> String {
    // Async Swift implementation
    return userData
}

Generated JavaScript/TypeScript:

export type Exports = {
    fetchUserData(userId: string): Promise<string>;
}

This enhancement significantly improves the developer experience when working with async Swift code in JavaScript environments, providing type-safe Promise-based APIs that feel natural in both languages.