Libraries: refresh the list after any sync that changes it

Only syncs started from the UI updated the list. One started in the backend, such as the sync after creating a library, left it stale: the new library kept saying it wasn't on the server yet, and Main stayed undeletable until the app reloaded. A sync that changes the libraries now emits an event the app refreshes on.

src-tauri/src/sync.rs

@@ -47,7 +47,7 @@ use mtgc_core::sync::remote::{
 };
 use mtgc_core::sync::{self as core_sync, LibraryDoc, MergeReport};
 use serde::Serialize;
-use tauri::{AppHandle, Manager};
+use tauri::{AppHandle, Emitter, Manager};
 
 use crate::state::{AppState, LocalLibrary, SyncAccount};
 
@@ -585,6 +585,11 @@ async fn run_sync(app: AppHandle, choice: Option<FirstSync>) -> Result<Option<Sy
         Err(e) => s.sync_error = Some(e.clone()),
     }
     drop(s);
+    // An event rather than the report alone: many syncs start here in the
+    // backend, with nothing in the UI waiting on their result.
+    if result.as_ref().is_ok_and(|r| r.libraries_changed) {
+        let _ = app.emit("libraries-changed", ());
+    }
     crate::logged("sync_now", result).map(Some)
 }