feat(api): expose vanished flag on episodes

crates/arr-daemon/src/series_refresh.rs

@@ -22,7 +22,7 @@
 //!
 //! Refresh is idempotent: over unchanged TMDB data only the stamp moves.
 
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::sync::Arc;
 
 use arr_core::tracking::{apply_auto_track, apply_tracked, RefreshedSeason};
@@ -354,14 +354,14 @@ impl SeriesRefreshAction {
         known: &HashMap<i64, (i64, String, Option<String>, bool)>,
         detail: &TmdbSeasonDetail,
     ) -> Result<bool, RefreshError> {
-        let upstream: HashMap<i64, ()> = detail
+        let upstream: HashSet<i64> = detail
             .episodes
             .iter()
-            .map(|source| (i64::from(source.number), ()))
+            .map(|source| i64::from(source.number))
             .collect();
         let mut changed = false;
         for (number, &(id, ..)) in known {
-            if upstream.contains_key(number) {
+            if upstream.contains(number) {
                 continue;
             }
             let has_file = sqlx::query_scalar!(