feat: 0.1.1 — timeline scrubber, gallery virtualisation, folder reorder, QoL polish

Timeline:
- Add a right-edge scrubber (year labels + month dots) that jumps to any
  period; runs in the same direction as the scrolled content
- Load the full filtered set in Timeline view so the scrubber spans the whole
  library instead of just the first page

Gallery & UI:
- Virtualise the gallery grid
- Folder reordering in the sidebar (drag + persisted sort_order) and a themed
  dropdown component
- Subtle Light theme contrast fixes for toggles, secondary buttons and the
  update toast

Embedding workers now defer video jobs without a thumbnail at claim time and
requeue any previously-failed deferred jobs on startup, so videos no longer
churn through failed embeddings.

QoL polish across BackgroundTasks, DuplicateFinder, Lightbox and VideoPlayer.

src-tauri/src/lib.rs

@@ -65,6 +65,11 @@ pub fn run() {
                 let conn = pool.get().expect("Failed to get connection for migration");
                 db::migrate(&conn).expect("Failed to run migrations");
                 db::reset_inflight_jobs(&conn).expect("Failed to reset inflight jobs");
+                let repaired_deferred = db::repair_deferred_embedding_jobs(&conn)
+                    .expect("Failed to repair deferred embedding jobs");
+                if repaired_deferred > 0 {
+                    log::info!("Requeued {repaired_deferred} deferred video embedding jobs.");
+                }
                 let backfilled =
                     db::backfill_embedding_jobs(&conn).expect("Failed to backfill embedding jobs");
                 if backfilled > 0 {
@@ -124,6 +129,7 @@ pub fn run() {
         .invoke_handler(tauri::generate_handler![
             commands::add_folder,
             commands::get_folders,
+            commands::reorder_folders,
             commands::get_background_job_progress,
             commands::remove_folder,
             commands::get_images,