feat(core): auto-track skips season 0

crates/arr-core/src/tracking.rs

@@ -11,13 +11,17 @@ pub struct RefreshedSeason {
 /// Applies a series' tracking rule to newly revealed seasons.
 ///
 /// Existing seasons keep their tracking rule and leaf-level intent unchanged.
-/// Season zero is treated like every other newly revealed season.
+/// Season 0 is never tracked by the rule (`DESIGN.md` §4.1); an operator may
+/// still track it by hand.
 pub fn apply_auto_track(series: &Series, seasons: &mut [RefreshedSeason]) {
     if !series.auto_track {
         return;
     }
 
-    for refreshed in seasons.iter_mut().filter(|season| season.is_new) {
+    for refreshed in seasons
+        .iter_mut()
+        .filter(|season| season.is_new && season.season.number != 0)
+    {
         refreshed.season.tracked = true;
         for episode in &mut refreshed.episodes {
             episode.wanted = true;
@@ -119,12 +123,12 @@ mod tests {
     }
 
     #[test]
-    fn season_zero_follows_the_same_rule() {
+    fn auto_track_skips_season_zero() {
         let mut refresh = [refreshed_season(0, true, &[false])];
 
         apply_auto_track(&series(true), &mut refresh);
 
-        assert!(refresh[0].season.tracked);
-        assert!(refresh[0].episodes[0].wanted);
+        assert!(!refresh[0].season.tracked);
+        assert!(refresh[0].episodes.iter().all(|episode| !episode.wanted));
     }
 }