[Infrastructure] Fix TypeScript build error for npm package update

[Copilot]

[Infrastructure] Fix TypeScript build error for npm package update

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Fix TypeScript 5.9.3 build error in StreamingInterop.ts

Description

TypeScript 5.9.3 introduced stricter type checking for Uint8Array. The subarray() method now returns Uint8Array<ArrayBufferLike> which isn't assignable to ArrayBufferView<ArrayBuffer> expected by ReadableByteStreamController.enqueue().

Changes:

• Changed ReadableStreamController<any> → ReadableStreamDefaultController<Uint8Array> for precise typing
• Added explicit ReadableStream<Uint8Array> type parameter
• Replaced data.subarray(0, bytesRead) with new Uint8Array(data.buffer, data.byteOffset, bytesRead) for type compatibility

Both approaches create a view (not a copy) of the underlying buffer, so runtime behavior is unchanged.

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