fix: remove auto-generated files from PR

Address metascroy review feedback: remove auto-generated files
(_generated_inspector, _generated_serializers, MLXLoader.cpp/h,
_generated/__init__.py) that should be regenerated by the build
system rather than checked in.

Kept only hand-authored changes: ops.py, test_ops.py,
mlx_graph_schema.py, schema.fbs.

Author: nanookclaw