Implement cuStreamCreate

[zluda-violet]

The last non-blasLt function needed for llm.c. I've put this in its own PR to declutter the blasLt one.

[Copilot]

Pull Request Overview

Implements the cuStreamCreate CUDA function by adding it to the function declarations and creating a corresponding implementation that maps to HIP's hipStreamCreateWithFlags.

• Added cuStreamCreate to the CUDA function declarations list
• Implemented the function in the stream module using HIP backend

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
zluda/src/lib.rs	Added cuStreamCreate to the macro-generated function declarations
zluda/src/impl/stream.rs	Added create function implementation that wraps hipStreamCreateWithFlags

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