mv ug to conditional target dep

assuming every non-wasm32 user wants this

candle-core/Cargo.toml

@@ -28,25 +28,26 @@ rand_distr = { workspace = true }
 rayon = { workspace = true }
 safetensors = { workspace = true }
 thiserror = { workspace = true }
-ug = { workspace = true, optional = true }
 ug-cuda = { workspace = true, optional = true }
 ug-metal = { workspace = true, optional = true }
 yoke = { workspace = true }
 zip = { workspace = true }
 
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+ug = { workspace = true }
+
 [dev-dependencies]
 anyhow = { workspace = true }
 clap = { workspace = true }
 criterion = { workspace = true }
 
-
 [features]
 default = []
-cuda = ["cudarc", "dep:candle-kernels", "dep:ug-cuda", "dep:ug"]
+cuda = ["cudarc", "dep:candle-kernels", "dep:ug-cuda"]
 cudnn = ["cuda", "cudarc/cudnn"]
 mkl = ["dep:libc", "dep:intel-mkl-src"]
 accelerate = ["dep:libc", "dep:accelerate-src"]
-metal = ["dep:metal", "dep:candle-metal-kernels", "dep:ug-metal", "dep:ug"]
+metal = ["dep:metal", "dep:candle-metal-kernels", "dep:ug-metal"]
 
 [[bench]]
 name = "bench_main"