## Motivation
This pr ports `fused_moe.py` and `fused_moe_kernels.py` to an NPU-affine
implementation while preserving the original math. The computational
definition is unchanged: forward remains `W1 (gate/up) -> SwiGLU -> W2
-> token-weighted gather`, and backward still follows `dA' = dO @ W2^T`
to produce `d_pre_act / dS / dW2 / dX / dW1`.
The main changes are execution-strategy optimizations for NPU.
## Note: Use the Skill
For this fused_moe kernel migration, we followed the skill document from
https://github.com/linkedin/Liger-Kernel/issues/1197.
## Testing Done
- Hardware Type: Ascend 910B2
- [x] run `make test` to ensure correctness
- [x] run `make checkstyle` to ensure code style
- [x] run `make test-convergence` to ensure convergence
🤖 Generated with: [cursor](https://cursor.com/).
Chunyu
e4831e4d64