feat: Major optimization and robustness improvements (#31)

This release introduces significant performance optimizations, memory efficiency
improvements, and enhanced system robustness:

🚀 Performance Optimizations:
- Add three new fused CUDA kernels (rope_index, rot_pos_emb, get_window_index)
  for accelerated multimodal preprocessing
- Implement FSDP2 support for distributed training with improved memory efficiency
- Add Torch.compile integration for additional performance gains
- Optimize memory usage: reduce peak allocation from 48GB to 24GB on 8-GPU setup

🔧 System Robustness:
- Fix missing token position inputs in prediction pipeline
- Add type-robust negation operations in RoPE CUDA kernels (half/bfloat16 support)
- Fix dataset root parameter initialization in LeRobot data loader
- Enhanced error handling and input validation across fusion operators

📚 Documentation & Usability:
- Add comprehensive memory usage benchmarks and hardware recommendations
- Update citation format with proper arXiv reference
- Improve training configuration documentation with quick start guide
- Add detailed API documentation for new fusion operators

🛠️ Technical Details:
- Version bump to 1.0.1
- New CUDA kernels: rope_index.cu, rot_pos.cu, window_index.cu
- FSDP2 state dict loading with distribute_tensor support
- Enhanced multimodal RoPE with 3D position encoding
- Window attention optimization for Vision Transformers

Breaking Changes: None - all changes are backward compatible

csrc/ops.cu

@@ -1,6 +1,9 @@
 #include "dual_asym_grouped_gemm.h"
 #include "permute.h"
 #include "rope.h"
+#include "rope_index.h"
+#include "rot_pos.h"
+#include "window_index.h"
 
 #include <torch/extension.h>
 
@@ -12,4 +15,7 @@ PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
   m.def("unpermute_bwd", &moe_recover_topK_bwd_op, "Token un-permutation backward kernel");
   m.def("rope", &launch_multimodal_rope_forward, "Multimodal RoPE forward kernel");
   m.def("rope_bwd", &launch_multimodal_rope_backward, "Multimodal RoPE backward kernel");
+  m.def("rope_index", &get_rope_index, "Get RoPE index kernel");
+  m.def("rot_pos_emb", &fused_rot_pos_emb_cuda, "Fused Rotary Position Embedding kernel");
+  m.def("get_window_index", &get_window_index_cuda, "Get window index kernel");
 }