[inference_fusion] convert conv3d patch embed to linear (#45041)
* ok
* fix consistency
* pass qwen35 reverse mapping
* update new failed test according to captured info
* Revert "update new failed test according to captured info"
This reverts commit 445a400123ef2ea2e56eab07615ddde8ea54f167.
* make it optional
* make fusion_mapping more general
* make conv3d conversion more general
* make fusion_mapping more general
* better name for conversion
* add fusion_mapping doc and clean tests
* fix reverse mapping test follow gemma3n
* chore: retrigger ci
* tests: move qwen3.5 reverse mapping fix to separate branch
* code clean!
* ruff format and clean test to make it simple
* richer doc
* get converters from config rather than each module
* add explict module_name check for fusion!
* better isolated test and code clean
* support serialized fusion_config
* ruff format
* config can handle unknown attributes
* move fused cls out of spec by mixin
* detailed comments
* ruff