T02: settings model, ranges, load and atomic save

Cargo.toml

@@ -10,11 +10,14 @@ publish = false
 
 [dependencies]
 anyhow = "1"
+dirs = "7"
 ely-gpui-component = { git = "https://git.zacharyzhang.com/ZacharyZhang-NY/Ely-GPUI-Components.git", rev = "12512217bd9bc652ed6bbf10461b00cc26c01c21" }
 env_logger = "0.11"
 gpui = { package = "gpui-pre", version = "=0.3.8", default-features = false }
 gpui_platform = { package = "gpui-pre-platform", version = "=0.3.8", features = ["font-kit", "wayland", "x11"] }
 log = "0.4"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
 
 [lints.rust]
 unexpected_cfgs = { level = "warn", check-cfg = ['cfg(feature, values("cargo-clippy"))'] }