feat(privacy): log warning on unknown ChatType in IsAllowedForStorage

F3.2: a future FFXIV patch can introduce ChatTypes that aren't on any
existing whitelist, and the filter currently routes them silently
through the unknown-channel failsafe. Add a dedup HashSet (per runtime,
NonSerialized) so the first hit per ChatType logs a Warning. The
failsafe behaviour itself is unchanged — only visibility is new.

HellionChat/Configuration.cs

@@ -64,12 +64,30 @@ public class Configuration : IPluginConfiguration
         .PrivacyDefaults
         .DefaultPersistUnknownChannels;
 
+    // F3.2: dedup unknown-ChatType warnings so a chatty filter doesn't spam
+    // the log every frame. NonSerialized so the warning fires once per
+    // runtime, not once-ever-per-install.
+    [NonSerialized]
+    private readonly HashSet<ChatType> _warnedUnknownChannels = new();
+
     public bool IsAllowedForStorage(ChatType type)
     {
         if (!PrivacyFilterEnabled)
             return true;
         if (PrivacyPersistChannels.Contains(type))
             return true;
+
+        // F3.2: log first occurrence so a new patch's ChatType doesn't drop
+        // off the radar. Failsafe still applies via PrivacyPersistUnknownChannels.
+        if (_warnedUnknownChannels.Add(type))
+        {
+            Plugin.Log.Warning(
+                "PrivacyFilter: unknown ChatType {Type} — falling back to PrivacyPersistUnknownChannels={Persist}.",
+                type,
+                PrivacyPersistUnknownChannels
+            );
+        }
+
         return PrivacyPersistUnknownChannels;
     }