Add `MoE_comm` category for dispatch/combine ops

[gphuang]

Tier 2 — Kimi K2 MoE communication

Scope:

• Add pattern matching for MoEDispatch, MoEDispatchBackward, MoECombine, MoECombineBackward, TokenPermuteMaskMap*
• TB/s perf model (these are permutation/scatter-gather ops)

Acceptance criteria:

• Kimi K2 MoE comm ops categorized correctly
• TB/s populated

[gphuang]

Follow-up to #518. This extends the MoE communication category introduced in #518 (PR #520) to cover Kimi-K2 ops (MoEDispatch, MoECombine, TokenPermuteMaskMap*). Will reuse the same EPComm perf model from PR #520.