[aot] Support multiple AOT runtime devices

[PENGUINLIONG]

Issue: #

Brief Summary

🤖 Generated by Copilot at 34529d5

Add Vulkan device selection and error handling to C-API. This allows users to specify a device_index for the Vulkan backend in taichi_core_impl.cpp, and raises an exception for invalid indices for other backends.

Walkthrough

🤖 Generated by Copilot at 34529d5

• Enable selecting a Vulkan device with the C-API by removing the zero check and calling set_vulkan_device_index with the device_index parameter (link)
• Add zero checks and error messages for the other backends that do not support selecting a device with the C-API: CUDA (link), Metal (link), OpenGL (link), CC (link), and LLVM (link)

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[ailzhang]

LGTM！