The dependency parser was stripping environment markers but not checking
if they indicated optional or platform-specific packages. This caused
packages like jaraco.path to pull in pyobjc (324 sub-packages) even on
non-macOS systems.
Changes:
- Filter dependencies with 'extra ==' markers (optional extras)
- Filter dependencies with 'sys_platform' or 'platform_system' markers
- Add diagnostic logging for depth exceeded errors
- Add unit tests for dependency filtering
Fixes tensorflow dependency resolution exceeding max depth.