refactor: api cleanup (#7812)

* refactor(config): unify YAML persistence

* refactor(config): remove redundant config APIs

* refactor(config): remove unused config APIs

* refactor(config): narrow profile APIs

* fix(config): preserve profiles on invalid reorder

* refactor(startup): narrow resolve helpers

* refactor(config): unify mixed port defaults

* refactor(network): simplify response APIs

* refactor(config): make profile builders infallible

* refactor(config): make profile activation infallible

* refactor(api): simplify internal runtime APIs

* refactor: consolidate internal config and window APIs

src-tauri/src/cmd/clash.rs

@@ -203,27 +203,17 @@ pub async fn apply_dns_config(apply: bool) -> CmdResult {
 }
 
 #[tauri::command]
-pub fn check_dns_config_exists() -> CmdResult<bool> {
-    use crate::utils::dirs;
-
-    let dns_path = dirs::app_home_dir().stringify_err()?.join(constants::files::DNS_CONFIG);
-
-    Ok(dns_path.exists())
-}
-
-#[tauri::command]
-pub async fn get_dns_config_content() -> CmdResult<String> {
+pub async fn get_dns_config_content() -> CmdResult<Option<String>> {
     use crate::utils::dirs;
     use tokio::fs;
 
     let dns_path = dirs::app_home_dir().stringify_err()?.join(constants::files::DNS_CONFIG);
 
-    if !fs::try_exists(&dns_path).await.stringify_err()? {
-        return Err("DNS config file not found".into());
+    match fs::read_to_string(&dns_path).await {
+        Ok(content) => Ok(Some(content.into())),
+        Err(error) if error.kind() == std::io::ErrorKind::NotFound => Ok(None),
+        Err(error) => Err(CommandFailure::plain(error)),
     }
-
-    let content = fs::read_to_string(&dns_path).await.stringify_err()?.into();
-    Ok(content)
 }
 
 #[tauri::command]

src-tauri/src/cmd/profile.rs

@@ -177,7 +177,7 @@ pub async fn delete_profile(index: String) -> CmdResult {
         }
     };
     if should_update {
-        logging_error!(Type::Config, profiles::activate_selected_nodes());
+        profiles::activate_selected_nodes();
     }
     drop(config_update_guard);
     drop(profile_write_guard);
@@ -241,7 +241,7 @@ async fn handle_success(current_value: Option<&String>) -> CmdResult<ValidationO
         .await
         .stringify_err()?;
     // Runtime refresh and tray rebuilding happen after saved node selections are restored.
-    profiles::activate_selected_nodes().stringify_err()?;
+    profiles::activate_selected_nodes();
 
     if let Err(e) = profiles_save_file_safe().await {
         logging!(warn, Type::Cmd, "Warning: 异步保存配置文件失败: {e}");

src-tauri/src/cmd/save_profile.rs

@@ -107,7 +107,7 @@ async fn restore_original(
 }
 
 fn profile_affects_runtime(profiles: &IProfiles, index: &str) -> bool {
-    let Some(current_uid) = profiles.get_current() else {
+    let Some(current_uid) = profiles.current.as_ref() else {
         return false;
     };
     if current_uid == index {