feat(git): make fetch command asynchronous for improved performance

The fetch command has been updated to run asynchronously, allowing for
better performance and responsiveness in the application. This change
ensures that the command does not block the main thread, enhancing the
user experience when interacting with repositories.

- Fetch command now uses async/await for non-blocking execution
- Added a grace period to prevent immediate background fetch after
  switching repositories
- Improved handling of authentication errors during fetch operations

src-tauri/src/git.rs

@@ -718,34 +718,38 @@ pub fn pull(
 }
 
 #[tauri::command]
-pub fn fetch(
+pub async fn fetch(
     path: String,
     username: Option<String>,
     password: Option<String>,
 ) -> Result<GitStatus, String> {
-    let repo = resolve_repo(&path)?;
-    let fetch_args = ["fetch"];
-    let output = match (username.as_deref(), password.as_deref()) {
-        (Some(u), Some(p)) if !u.is_empty() || !p.is_empty() => {
-            run_git_authenticated_output(&repo, fetch_args, u, p)?
+    tauri::async_runtime::spawn_blocking(move || -> Result<GitStatus, String> {
+        let repo = resolve_repo(&path)?;
+        let fetch_args = ["fetch"];
+        let output = match (username.as_deref(), password.as_deref()) {
+            (Some(u), Some(p)) if !u.is_empty() || !p.is_empty() => {
+                run_git_authenticated_output(&repo, fetch_args, u, p)?
+            }
+            _ => git_command()
+                .arg("-C")
+                .arg(&repo)
+                .args(fetch_args)
+                .output()
+                .map_err(|err| format!("Could not start Git. Is Git installed? {err}"))?,
+        };
+
+        if output.status.success() {
+            return status_for_repo(&repo);
         }
-        _ => git_command()
-            .arg("-C")
-            .arg(&repo)
-            .args(fetch_args)
-            .output()
-            .map_err(|err| format!("Could not start Git. Is Git installed? {err}"))?,
-    };
 
-    if output.status.success() {
-        return status_for_repo(&repo);
-    }
-
-    let details = command_output_details(&output);
-    if is_auth_error(&details) {
-        return Err(format!("AUTH_FAILED:{details}"));
-    }
-    Err(format!("Git command failed: {details}"))
+        let details = command_output_details(&output);
+        if is_auth_error(&details) {
+            return Err(format!("AUTH_FAILED:{details}"));
+        }
+        Err(format!("Git command failed: {details}"))
+    })
+    .await
+    .map_err(|err| format!("Could not fetch repository: {err}"))?
 }
 
 #[tauri::command]