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-tensor-testgen/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+authors = ["nathanielsimard <nathaniel.simard.42@gmail.com>"]
+description = "Test generation crate for burn-tensor"
+edition.workspace = true
+license.workspace = true
+name = "burn-tensor-testgen"
+readme.workspace = true
+repository = "https://github.com/tracel-ai/burn/tree/main/crates/burn-tensor-testgen"
+version.workspace = true
+
+[lints]
+workspace = true
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = { workspace = true }
+quote = { workspace = true }
+syn = { workspace = true }