refactor(store): route MessageStore IsWine probe through IPlatformUtil (F12.1)

MessageStore.Connect used to call Util.IsWine() directly via a
DalamudUtil alias, which made the ctor unreachable from the xUnit
test AppDomain: any test that allocated a MessageStore tripped a
FileNotFoundException on Dalamud.dll before reaching the assertion.

The ctor now takes an IPlatformUtil and reads the cached IsWine
property. MessageManager passes Plugin.PlatformUtil in. Production
behaviour is identical; the test path can now substitute a fake
and exercise the SQLite migration logic in isolation.

HellionChat/MessageManager.cs

@@ -52,7 +52,7 @@ internal class MessageManager : IAsyncDisposable
     {
         Plugin = plugin;
 
-        Store = new MessageStore(DatabasePath());
+        Store = new MessageStore(DatabasePath(), Plugin.PlatformUtil);
 
         PendingMessageThread = new Thread(() =>
             ProcessPendingMessages(PendingThreadCancellationToken.Token)

HellionChat/MessageStore.cs

@@ -9,7 +9,6 @@ using MessagePack;
 using MessagePack.Formatters;
 using MessagePack.Resolvers;
 using Microsoft.Data.Sqlite;
-using DalamudUtil = Dalamud.Utility.Util;
 using Encoding = System.Text.Encoding;
 
 namespace HellionChat;
@@ -137,9 +136,12 @@ internal class MessageStore : IDisposable
             )
         );
 
-    internal MessageStore(string dbPath)
+    private readonly IPlatformUtil _platformUtil;
+
+    internal MessageStore(string dbPath, IPlatformUtil platformUtil)
     {
         DbPath = dbPath;
+        _platformUtil = platformUtil;
         Connection = Connect();
         Migrate();
     }
@@ -166,7 +168,7 @@ internal class MessageStore : IDisposable
         conn.Open();
         conn.Execute(@"PRAGMA journal_mode=WAL;");
         conn.Execute(@"PRAGMA synchronous=NORMAL;");
-        if (DalamudUtil.IsWine())
+        if (_platformUtil.IsWine)
             conn.Execute(@"PRAGMA cache_size = 32768;");
         return conn;
     }