Apply the community-rating floor to rated titles as well

The audience tag admitted any title whose official rating sat at or below the
ceiling, with no quality condition at all. The community-rating floor was only
consulted when a title had no usable rating. On a real library that let 21
poorly reviewed but mildly rated titles through - Norbit, Cats, Super Mario
Bros., Rocky V, Cool as Ice among them - none of which belong in a library whose
entire purpose is to be smaller than the one it was carved out of. A ceiling
answers whether a title is suitable; it says nothing about whether it is worth
offering.

MinCommunityRating now applies to rated titles, alongside the existing
MinCommunityRatingWhenUnrated for titles with no rating to judge. The two are
separate settings because an unrated title carries more uncertainty and may
warrant a higher bar. A rated title with no community rating at all now fails,
which is deliberate: with neither a score to check nor a reputation to weigh,
there is nothing to decide on.

Verified against the live library: a full pass over 2778 titles settles at 561
tagged, and the 21 are not re-added.

Jellyfin.Plugin.Audience/Configuration/PluginConfiguration.cs

@@ -51,6 +51,15 @@ public class PluginConfiguration : BasePluginConfiguration
     /// </remarks>
     public int MaxRatingScore { get; set; } = 14;
 
+    /// <summary>
+    /// Gets or sets the community rating an item must reach to be tagged when it DOES have a
+    /// usable official rating. The ceiling alone is not enough: this tag exists to make an
+    /// overwhelming library smaller, and a poorly reviewed film that happens to be rated PG
+    /// adds noise rather than removing it. An item carrying no community rating at all fails
+    /// this check, which is deliberate.
+    /// </summary>
+    public double MinCommunityRating { get; set; } = 6.0;
+
     /// <summary>
     /// Gets or sets the minimum community rating for an item with no usable parental rating.
     /// </summary>