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-fusion/Cargo.toml

@@ -0,0 +1,42 @@
+[package]
+authors = ["nathanielsimard <nathaniel.simard.42@gmail.com>"]
+categories = ["science"]
+description = "Kernel fusion backend decorator for the Burn framework"
+edition.workspace = true
+keywords = ["deep-learning", "machine-learning", "data"]
+license.workspace = true
+name = "burn-fusion"
+readme.workspace = true
+repository = "https://github.com/tracel-ai/burn/tree/main/crates/burn-fusion"
+documentation = "https://docs.rs/burn-fusion"
+version.workspace = true
+
+[lints]
+workspace = true
+
+[features]
+default = ["std", "tracing"]
+std = ["serde/std", "tracing?/std"]
+doc = ["default"]
+memory-checks = ["std"]
+
+tracing = [
+    "dep:tracing",
+    "burn-backend/tracing",
+    "burn-ir/tracing",
+]
+
+[dependencies]
+burn-backend = { path = "../burn-backend", version = "=0.21.0-pre.2" }
+burn-ir = { path = "../burn-ir", version = "=0.21.0-pre.2" }
+tracing = { workspace = true, optional = true, features = ["attributes"] }
+
+hashbrown = { workspace = true }
+derive-new = { workspace = true }
+spin = { workspace = true }
+log = { workspace = true }
+serde = { workspace = true }
+
+[package.metadata.docs.rs]
+features = ["doc"]
+rustdoc-args = ["--cfg", "docsrs"]