feat: local backup (#5054)

* feat: local backup

* refactor(backup): make local backup helpers synchronous and clean up redundant checks

- Converted local backup helpers to synchronous functions to remove unused async warnings and align command signatures.
- Updated list/delete/export commands to call the sync feature functions directly without awaits while preserving behavior.
- Simplified destination directory creation to always ensure parent folders exist without redundant checks, satisfying Clippy.

src-tauri/src/cmd/backup.rs

@@ -0,0 +1,33 @@
+use super::CmdResult;
+use crate::{feat, wrap_err};
+use feat::LocalBackupFile;
+
+/// Create a local backup
+#[tauri::command]
+pub fn create_local_backup() -> CmdResult<()> {
+    wrap_err!(feat::create_local_backup())
+}
+
+/// List local backups
+#[tauri::command]
+pub fn list_local_backup() -> CmdResult<Vec<LocalBackupFile>> {
+    wrap_err!(feat::list_local_backup())
+}
+
+/// Delete local backup
+#[tauri::command]
+pub fn delete_local_backup(filename: String) -> CmdResult<()> {
+    wrap_err!(feat::delete_local_backup(filename))
+}
+
+/// Restore local backup
+#[tauri::command]
+pub async fn restore_local_backup(filename: String) -> CmdResult<()> {
+    wrap_err!(feat::restore_local_backup(filename).await)
+}
+
+/// Export local backup to a user selected destination
+#[tauri::command]
+pub fn export_local_backup(filename: String, destination: String) -> CmdResult<()> {
+    wrap_err!(feat::export_local_backup(filename, destination))
+}