build(ascend): compile direct2560 grouped matmul from source

[xieminghui187]

Summary

• keep the existing prebuilt-artifact delivery in Bundle direct2560 grouped matmul for Ascend #351 unchanged
• remove committed Ascend OPP binaries and generated kernel artifacts in this separate source-build alternative
• compile the direct2560 ACLNN operator during wheel build and package only runtime libraries/header
• move the MoE2560 diagnostic log out of the execution hot path and remove redundant Python-side hot-path validation

Validation

• clean PEP 517 wheel build on Ascend CANN 8.5
• wheel contains no kernel .o/kernel JSON/OPP source tree
• FP16 NPU correctness: max abs error 0.0
• BF16 NPU correctness: max abs error 0.0
• BF16 100-iteration stability: pass, max abs error 0.0

This is intentionally a separate Draft PR so #351 remains available as the already-accepted basic delivery.

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