Tauri runs commands declared without `async` on the main thread, so Local History, shelf, change-list and run-configuration reads and writes, `.env` loading and the line diff of two arbitrary texts blocked input, painting and every other IPC call while they ran. They are now async and run on the blocking pool; IPC signatures are unchanged. `vcs_changelists_save` stays synchronous so its fire-and-forget saves land in order. A guard test keeps these commands async.
Co-authored-by: rohitdanda <10144914+rohitdanda@users.noreply.github.com>