fix(build): 回退qwen3_6_scripts+ex_engine到26e6cb40(能得分版本)

唯一改动: computility-run.yaml max_model_len 80000→100000

26e6cb40是Sub520能在竞赛平台docker build成功并得分的版本
之后所有commit都导致docker build失败
根因: 新增的65个文件(vendor_overrides/prebuilt/*.so/wheels等)
可能触发了竞赛平台docker build的某个限制

本次回退:
- qwen3_6_scripts/: 110→45文件(删掉65个新增文件)
- ex_engine/: 恢复到26e6cb40完全一致
- Dockerfile: 恢复5个RUN步骤结构(已验证能build)
- computility-run.yaml: max_model_len=100000(避免replay 400拒绝)

ex_engine/python/__init__.py

@@ -1,16 +1,3 @@
 from .ex_loader import EXEngine, get_engine
 
 __all__ = ["EXEngine", "get_engine"]
-
-# Lazy imports for new modules (don't break if deps missing)
-def __getattr__(name):
-    if name == "ix":
-        from .ix_unified import ix
-        return ix
-    if name == "gdn_fp32":
-        from . import gdn_fp32
-        return gdn_fp32
-    if name == "moe_dispatch":
-        from . import moe_dispatch
-        return moe_dispatch
-    raise AttributeError(f"module 'ex_engine.python' has no attribute {name}")