Stage 4 of TinyTorch API simplification:
- Added flatten() and max_pool2d() helper functions
- Renamed MultiChannelConv2D to Conv2d for PyTorch compatibility
- Updated Conv2d to inherit from Module base class
- Use Parameter() for weights and bias with automatic registration
- Added backward compatibility alias: MultiChannelConv2D = Conv2d
- Updated all test code to use Conv2d
- Exported changes to tinytorch.core.spatial
API now provides PyTorch-like spatial operations while maintaining
educational value of implementing core convolution algorithms.
- Regenerate all .ipynb files from fixed .py modules
- Update tinytorch package exports with corrected implementations
- Sync package module index with current 16-module structure
These generated files reflect all the module fixes and ensure consistent
.py ↔ .ipynb conversion with the updated module implementations.