[NPU] add A5 support for A2E and E2A ops

[wangyibo1005]

A5 HCCL rejects the 910C MC2 tiling/window ABI, so register CANN 9.1 ascend950 and the CANN 8.5 ascend910_95 alias, use the MTE comm engine, and read A5 window addresses without changing the 910C path.

PLEASE FILL IN THE PR DESCRIPTION AND MAKE SURE THE CHECKLIST ITEMS HAVE BEEN CONSIDERED.

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Essential PR Checklist

• Purpose is clear and linked to public context when possible.
• Scope is bounded.
• Compatibility with vLLM v0.26.0 is considered.
• No changes are made to the vLLM source checkout.
• Plugin-owned classes or explicit dotted class paths are preferred over monkey patches.
• Any compat shim or monkey patch is isolated, idempotent, version-guarded, documented, and tested.
• Imports remain CPU-safe; CUDA-heavy work is delayed or GPU-gated.
• Validation evidence is included, including skipped GPU tests when applicable.
• Documentation impact is stated.

[jiangkuaixue123]

Thanks for adding A5 support! Has this change also been validated on A3? Could you please run the relevant A3 test cases as well?