[draft] support ATOM plugin for qwen3.5 DPxTPx/DPxEPx

[zovonoir]

Enable qwen3.5 series DPEP/DPTP feature, testing.

[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 1690 --add-label <label>

[github-actions]

⚠️ [ruff] <SIM117> _{reported by reviewdog 🐶}
Use a single with statement with multiple contexts instead of nested with statements

[github-actions]

⚠️ [ruff] <SIM117> _{reported by reviewdog 🐶}
Use a single with statement with multiple contexts instead of nested with statements

[github-actions]

⚠️ [ruff] <I001> _{reported by reviewdog 🐶}
Import block is un-sorted or un-formatted

ATOM/atom/plugin/sglang/models/qwen3_5.py

Lines 4 to 48 in 59fe613

	from __future__ import annotations
	from contextlib import contextmanager
	from collections.abc import Iterable
	from typing import Any, Optional
	import torch
	from torch import nn
	from atom.plugin.sglang.runtime import (
	SGLangForwardBatchMetadata,
	SGLangPluginRuntime,
	plugin_runtime_scope,
	)
	from aiter.dist.parallel_state import get_pp_group as _aiter_pp_group
	from sglang.srt.layers.quantization.base_config import (
	QuantizationConfig as SGLangQuantizationConfig,
	)
	from sglang.srt.model_executor.forward_batch_info import (
	ForwardBatch,
	PPProxyTensors,
	)
	from sglang.srt.models.qwen3_5 import (
	Qwen3_5ForConditionalGeneration as _SglQwen35VL,
	Qwen3_5MoeForConditionalGeneration as _SglQwen35MoeVL,
	)
	from atom.model_loader.loader import WeightsMapper
	from atom.models.qwen3_5 import (
	Qwen3_5ForCausalLM,
	Qwen3_5ForCausalLMBase,
	Qwen3_5Model,
	Qwen3_5MoeForCausalLM,
	detect_fused_expert_format,
	get_fused_expert_mapping,
	load_fused_expert_weights,
	)
	from atom.models.utils import IntermediateTensors
	from atom.plugin.sglang.attention_backend.attention_gdn import (
	SGLangGDNForwardContext,
	)
	from atom.plugin.sglang.runtime import (
	SGLangForwardBatchMetadata,
	)