fix: respect no merge tag

If you want a series to never be merged, then (potentially create and) add the `"shokofin/no merge"` custom tag on the series in shoko server, and it will never be merged with another series in the plugin.

Author: revam

Shokofin/API/ShokoAPIManager.cs

@@ -851,6 +851,10 @@ private async Task<SeasonInfo> CreateSeasonInfo(Series series)
                 if (series.AniDBEntity.AirDate is null)
                     return (primaryId, extraIds);
 
+                var customTags = await GetNamespacedTagsForSeries(primaryId).ConfigureAwait(false);
+                if (customTags.ContainsKey("/custom user tags/shokofin/no merge"))
+                    return (primaryId, extraIds);
+
                 Logger.LogTrace("Creating new series-to-season mapping for series. (Series={SeriesId})", primaryId);
 
                 // We potentially have a "follow-up" season candidate, so look for the "primary" season candidate, then jump into that.
@@ -886,6 +890,10 @@ private async Task<SeasonInfo> CreateSeasonInfo(Series series)
                                     continue;
                             }
 
+                            var prequelCustomTags = await GetNamespacedTagsForSeries(prequelSeries.IDs.Shoko.ToString()).ConfigureAwait(false);
+                            if (prequelCustomTags.ContainsKey("/custom user tags/shokofin/no merge"))
+                                continue;
+
                             var prequelMainTitle = prequelSeries.AniDBEntity.Titles.First(title => title.Type == TitleType.Main).Value;
                             var prequelResult = YearRegex.Match(prequelMainTitle);
                             if (!prequelResult.Success) {
@@ -937,6 +945,10 @@ private async Task<SeasonInfo> CreateSeasonInfo(Series series)
                                         continue;
                                 }
 
+                                var sequelCustomTags = await GetNamespacedTagsForSeries(sequelSeries.IDs.Shoko.ToString()).ConfigureAwait(false);
+                                if (sequelCustomTags.ContainsKey("/custom user tags/shokofin/no merge"))
+                                    continue;
+
                                 var sequelMainTitle = sequelSeries.AniDBEntity.Titles.First(title => title.Type == TitleType.Main).Value;
                                 var sequelResult = YearRegex.Match(sequelMainTitle);
                                 if (!sequelResult.Success)