feat: update workspace paths and enhance gitignore

- Updated stablediffusion crate path from "../stable-diffusion-burn" to "./crates/stable-diffusion-burn" for proper workspace resolution
- Enhanced .gitignore to include generated model files (.mpk, .pt, .bin, .safetensors, .ckpt) and user_data directory
- Added Cargo.lock to gitignore with appropriate comment
- Reorganized IDE files section in gitignore for better clarity
- Added newline at end of file for proper formatting

crates/stable-diffusion-burn/burn-crates/burn-cpu/README.md

@@ -0,0 +1,12 @@
+# Burn CPU Backend
+
+[Burn](https://github.com/tracel-ai/burn) CubeCL CPU backend
+
+[![Current Crates.io Version](https://img.shields.io/crates/v/burn-cuda.svg)](https://crates.io/crates/burn-cuda)
+
+This crate provides a MLIR based CPU backend for [Burn](https://github.com/tracel-ai/burn) using the
+[cubecl](https://github.com/tracel-ai/cubecl.git) crates.
+
+## Usage Example
+
+Example coming soon