Fix thumbnail lifecycle failures

crates/pdfs-fuse/src/mount.rs

@@ -395,7 +395,9 @@ pub fn mount(
         file_thumb_generation: Arc::new(AtomicU64::new(0)),
         file_thumb_cancel: Arc::new(tokio::sync::Notify::new()),
         thumbnail_build: Arc::new(Mutex::new(Default::default())),
-        no_thumbnail: Arc::new(Mutex::new(HashMap::new())),
+        thumbnail_build_cancelled: Arc::new(AtomicBool::new(false)),
+        thumbnail_build_cancel: Arc::new(tokio::sync::Notify::new()),
+        thumbnail_misses: Arc::new(Mutex::new(Default::default())),
         quota: Arc::new(Mutex::new(None)),
         size_upgrades: Arc::new(Mutex::new(HashMap::new())),
         size_waiters: Arc::new(Default::default()),