fix: guard series metadata from episode identity pollution

internal/service/scraper.go

@@ -212,26 +212,34 @@ func (s *ScraperService) matchFromMediaExternalIDs(ctx context.Context, m *model
 			mediaType = "tv"
 		}
 		if match := s.manualTMDbMatchByID(ctx, m.TMDbID, normalizeMediaType(mediaType, m.Title, "")); match != nil {
-			return match
+			if s.mediaExternalIDMatchTrusted(m, lib, match, "tmdb") {
+				return match
+			}
 		}
 	}
 	if strings.TrimSpace(m.DoubanID) != "" && s.douban != nil && s.douban.Enabled() {
 		if match, err := s.douban.GetMatchByID(ctx, strings.TrimSpace(m.DoubanID)); err == nil && match != nil {
-			return match
+			if s.mediaExternalIDMatchTrusted(m, lib, match, "douban") {
+				return match
+			}
 		} else if err != nil {
 			s.log.Debug("douban id lookup failed", zap.String("media_id", m.ID), zap.String("douban_id", m.DoubanID), zap.Error(err))
 		}
 	}
 	if m.BangumiID > 0 && s.bangumi != nil && s.bangumi.Enabled() {
 		if match, err := s.bangumi.GetSubject(ctx, m.BangumiID); err == nil && match != nil {
-			return match
+			if s.mediaExternalIDMatchTrusted(m, lib, match, "bangumi") {
+				return match
+			}
 		} else if err != nil {
 			s.log.Debug("bangumi id lookup failed", zap.String("media_id", m.ID), zap.Int("bangumi_id", m.BangumiID), zap.Error(err))
 		}
 	}
 	if strings.TrimSpace(m.TheTVDBID) != "" && s.thetvdb != nil && s.thetvdb.Enabled() {
 		if match, err := s.thetvdb.GetSeriesMatchByID(ctx, strings.TrimSpace(m.TheTVDBID)); err == nil && match != nil {
-			return match
+			if s.mediaExternalIDMatchTrusted(m, lib, match, "thetvdb") {
+				return match
+			}
 		} else if err != nil {
 			s.log.Debug("thetvdb id lookup failed", zap.String("media_id", m.ID), zap.String("thetvdb_id", m.TheTVDBID), zap.Error(err))
 		}
@@ -239,6 +247,35 @@ func (s *ScraperService) matchFromMediaExternalIDs(ctx context.Context, m *model
 	return nil
 }
 
+func (s *ScraperService) mediaExternalIDMatchTrusted(m *model.Media, lib *model.Library, match *Match, source string) bool {
+	if match == nil || strings.TrimSpace(match.Title) == "" {
+		return false
+	}
+	if !mediaIsEpisodic(m, lib) {
+		return true
+	}
+	for _, candidate := range scrapeQueryCandidates(m, lib) {
+		if unsafeAutomaticEpisodeQuery(candidate) {
+			continue
+		}
+		if automaticMetadataTitleTrusted(candidate, match) {
+			return true
+		}
+	}
+	if s != nil && s.log != nil && m != nil {
+		s.log.Warn("episode external id match rejected",
+			zap.String("media_id", m.ID),
+			zap.String("source", source),
+			zap.String("title", match.Title),
+			zap.String("original_name", match.OriginalName),
+			zap.Int("tmdb_id", match.TMDbID),
+			zap.Int("bangumi_id", match.BangumiID),
+			zap.String("douban_id", match.DoubanID),
+			zap.String("thetvdb_id", match.TheTVDBID))
+	}
+	return false
+}
+
 func (s *ScraperService) applyFanartArtwork(ctx context.Context, match *Match) {
 	if s == nil || s.fanart == nil || !s.fanart.Enabled() || match == nil {
 		return
@@ -274,6 +311,12 @@ func mediaYearHint(m *model.Media) int {
 	if m == nil {
 		return 0
 	}
+	if m.SeasonNum > 0 || m.EpisodeNum > 0 {
+		return seriesPathYearHint(m.Path)
+	}
+	if season, episode := ParseEpisode(m.Path); season > 0 || episode > 0 {
+		return seriesPathYearHint(m.Path)
+	}
 	if m.Year > 0 {
 		return m.Year
 	}
@@ -283,6 +326,15 @@ func mediaYearHint(m *model.Media) int {
 	return yearFromText(m.Path)
 }
 
+func seriesPathYearHint(path string) int {
+	if showDir := showDirFromEpisodePath(path); showDir != "" {
+		if _, year := CleanQuery(showDir); year > 0 {
+			return year
+		}
+	}
+	return 0
+}
+
 func yearFromText(raw string) int {
 	if raw == "" {
 		return 0