Proposal: add TestBaseVCI support to python-can

首先检查现有的、单独分发的 hrcan 后端和 HRCANBus，然后检查用于注册的 can.interfaces.BACKENDS 入口点。确认 TestBaseVCI SDK 和驱动程序的假设如何与 python-can 相匹配，并确定所提议的适配器支持 CAN/CAN FD，且不会影响其他设备的用户。

Hi maintainers,

We are a company that develops CAN bus communication and simulation products, and I'd like to ask whether support for our TestBaseVCI CAN / CAN FD hardware could be accepted in python-can.

We already have a working backend for it, and it has been used for quite a while as a separately distributed extension. The current backend name is hrcan, with bus class HRCANBus.

Current status:

• supports classic CAN and CAN FD
• has been used in practice for a long time
• currently installed manually by copying files into the Python environment and registering it in can.interfaces.BACKENDS

Environment:

• Windows 10 / 11
• Ubuntu 20 / 22
• 64-bit Python
• TestBaseVCI driver >= 2.4.1
• currently used with python-can 4.5.0

Supported features:

• start CAN / CAN FD channels with different bus parameters
• send / receive single frames
• periodic transmission, with manual and logger-based receive flows
• multi-device support
• multi-process support
• unified timestamp behavior

A few notes before I prepare a PR:

• I will only submit the Python-layer adapter code to python-can
• if a user wants to use our hardware but has not installed the SDK / device driver, I can provide a public SDK download link and a clear text reminder
• I will make sure that if users do not use our device, this support will not affect any existing python-can functionality

If this direction looks okay, I'm happy to clean it up and prepare a PR. I'd also appreciate any suggestions before I start.

Thanks.