Apply OS theme via native-theme on desktop

crates/settings/src/lib.rs

@@ -35,6 +35,24 @@ pub fn init(cx: &mut App) {
     AppSettings::set_global(cx.new(AppSettings::new), cx)
 }
 
+/// Read the persisted appearance mode synchronously.
+///
+/// The async load fills the global settings later; the native theme must be
+/// applied before the first window opens, so boot reads the mode straight
+/// from the settings file instead.
+pub fn persisted_appearance_mode() -> AppearanceMode {
+    #[cfg(not(target_arch = "wasm32"))]
+    {
+        let path = config_dir().join(".settings");
+        if let Ok(content) = std::fs::read_to_string(path)
+            && let Ok(settings) = serde_json::from_str::<Settings>(&content)
+        {
+            return settings.appearance_mode;
+        }
+    }
+    AppearanceMode::default()
+}
+
 const DEFAULT_FILE_SERVER: &str = "https://nostr.download/";
 const LEGACY_FILE_SERVER: &str = "blossom.band";