[ci][mesh] improve ATOMesh benchmark configuration and dashboard reporting

[wanzhenchn]

Motivation

• Isolated ATOMesh worker compile caches to avoid cross-worker cache conflicts.
• Improved ATOMesh benchmark case selection and configuration.
• Updated Kimi-K2 environment settings.
• Fixed dashboard rerun result selection by throughput.
• Split ATOMesh dashboard charts by model for clearer comparison.

[github-actions]

🏷️ CI Guide

Runs automatically on every eligible PR before approval:

• ✅ Pre Checkin: Black, Ruff, catalog schema validation, non-GPU unit tests

Heavy model tests:

• ✅ Run after the PR is approved and Pre Checkin passes
• ✅ Run immediately when an approval review is submitted
• ✅ Can be requested before approval with labels

Label	Tests
ci:full	Run all heavy PR model tests: native ATOM, vLLM, and SGLang
ci:atom	Run native ATOM model accuracy tests
ci:vllm	Run ATOM vLLM OOT model accuracy tests
ci:sglang	Run ATOM SGLang model accuracy tests

Heavy jobs are skipped when the PR is not approved and no matching ci:* label is present.
Add labels via the sidebar or gh pr edit 1580 --add-label <label>

[Yuechguo]

LGTM