Removed layerwise infra from efficient transformers

[abhishek-singh591]

Remove Layerwise Infrastructure

Summary

This change removes the layerwise export and compilation infrastructure from
QEfficient. Standard full-model ONNX export and compilation remain the supported
deployment path.

What Changed

• Removed layerwise model-windowing, ONNX splitting, merging, prefixing, and
  per-window compilation helpers.
• Removed layerwise-specific ONNX export patches and cache-probe handling.
• Removed the layerwise argument from model loading, export, and compile
  call sites.
• Simplified Qwen3 MoE, Qwen3.5 MoE, and Qwen3-VL MoE wrappers to use the
  standard export and compilation flow.
• Removed layerwise-only example scripts and test fixtures.
• Removed the layerwise onnx-ir==0.2.1 setup requirement from
  examples/README.md.

Removed Interfaces

The following implementation modules are removed and must not be imported by
downstream code:

• QEfficient.transformers.models._layerwise
• QEfficient.utils.compile_layerwise
• QEfficient.utils.layerwise_pipeline

Any caller that passes layerwise=True or layerwise=False must remove that
argument. Layerwise-specific compile options, including internal
_layerwise_cache_probe, are no longer supported.

Migration

Use the existing model load, export, and compile APIs without layerwise
arguments. For example:

from QEfficient import QEFFAutoModelForCausalLM

qeff_model = QEFFAutoModelForCausalLM.from_pretrained(model_id)

qpc_path = qeff_model.compile(
    batch_size=1,
    prefill_seq_len=128,
    ctx_len=4096,
    num_cores=16,
)

The standard export path produces deployment artifacts directly and does not
require a layer-window split/merge pipeline.

Removed Examples

• examples/disagg_serving/qwen3moe_layerwise.py
• examples/image_text_to_text/models/qwen3_5_moe/qwen3_5_moe_layerwise.py

Existing disaggregated-serving examples remain available; their layerwise
arguments have been removed.

Compatibility Impact

This is a breaking change only for users of the layerwise APIs, helper modules,
or example scripts. Users of the standard QEfficient export and compile APIs do
not need to change their workflow, except to remove any explicit layerwise
arguments.

[abhishek-singh591]

CI-Ready

[ochougul]

CI-Ready

[ochougul]

CI-Ready

[ochougul]

CI-Ready

[ochougul]

CI-Ready

[github-actions]

This pull request has been marked as stale due to 30 days of inactivity. To prevent automatic closure in 5 days, remove the stale label or add a comment. You can reopen a closed pull request at any time.