feat(guild): repositories for Guild aggregate

SVSim.Database/Repositories/Guild/IGuildChatMessageRepository.cs

@@ -0,0 +1,20 @@
+using SVSim.Database.Entities.Guild;
+
+namespace SVSim.Database.Repositories.Guild;
+
+public interface IGuildChatMessageRepository
+{
+    /// <summary>Atomically allocate the next per-guild message_id and insert.</summary>
+    Task<GuildChatMessage> AppendAsync(GuildChatMessage msg, CancellationToken ct = default);
+
+    /// <summary>Window query. direction: 1=OLD (asc-walk older), 2=NEW (newer), 3=BOTH (around).
+    /// `start` may be 0 meaning "latest". Returns ordered oldest-to-newest.</summary>
+    Task<IReadOnlyList<GuildChatMessage>> GetWindowAsync(int guildId, int start, int direction, int limit, CancellationToken ct = default);
+
+    Task<int> GetMaxMessageIdAsync(int guildId, CancellationToken ct = default);
+    Task DeleteAllForGuildAsync(int guildId, CancellationToken ct = default);
+
+    /// <summary>For /guild_chat/delete_deck: clears the deck payload + body without removing the message row,
+    /// so the slot remains in the timeline ("[deleted]"). Returns false if not found / not deletable by caller.</summary>
+    Task<bool> ClearDeckAsync(int guildId, int messageId, long callerViewerId, CancellationToken ct = default);
+}