try to support gemma4

[wenhuach21]

Description

Please briefly describe your main changes, the motivation.

Type of Change

• Bug fix
• New feature
• Documentation update
• Performance improvement
• Code refactoring
• Other (please specify):

Related Issues

Fixes or relates to #

Checklist Before Submitting

• My code has been tested locally.
• Documentation has been updated as needed.
• New or updated tests are included where applicable.

[Copilot]

Pull request overview

This PR aims to add initial support for the gemma4 model family by adapting block input caching/quantization flow to handle variable block shapes and extra cached inputs.

Changes:

• Allow wrapper blocks to forward positional args through to decoder layers.
• Add a predefined fixed-attribute lookup for special model types (gemma4).
• Extend caching/quantization to support variable-shaped block groupings and extra per-block cached inputs.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 9 comments.

File	Description
auto_round/wrapper.py	Forwards positional args through WrapperMultiblock.forward to improve model compatibility.
auto_round/special_model_handler.py	Introduces predefined fixed attributes (e.g., gemma4) retrievable from model.config.model_type.
auto_round/compressors/base.py	Uses fixed attributes to alter block caching/quantization for variable block shapes and additional cached inputs.

[wenhuach21]

TODO @n1ck-guo I'll leave it to you

1 consolidate with your pr. While this pr is more general, it costs large vram during calibration.

2 Add an argument to the API to allow users to configure this, since it’s not easy to determine whether a model has variable block inputs. One possible approach is to probe with sample data, but that would require loading all the blocks, which is costly.