fix(styling): fullscreen kraft paper bg, persistence preset refresh, reader cleanup

src/persistence.rs

@@ -25,8 +25,20 @@ pub fn load_settings(dir: &Path) -> Result<Settings, String> {
     let path = dir.join(SETTINGS_FILE);
     let json = std::fs::read_to_string(&path)
         .map_err(|e| format!("读取设置失败: {}", e))?;
-    serde_json::from_str(&json)
-        .map_err(|e| format!("解析设置失败: {}", e))
+    let mut settings: Settings = serde_json::from_str(&json)
+        .map_err(|e| format!("解析设置失败: {}", e))?;
+    // Always refresh profiles from code-defined presets so that updated
+    // preset values (font size, spacing, etc.) take effect even when
+    // an older settings.json is present on disk.
+    let preset_names: Vec<String> = crate::style::StyleProfile::presets()
+        .iter()
+        .map(|p| p.name.clone())
+        .collect();
+    settings.profiles = crate::style::StyleProfile::presets();
+    if !preset_names.contains(&settings.active_profile) {
+        settings.active_profile = "Kindle 默认".into();
+    }
+    Ok(settings)
 }
 
 #[cfg(test)]