feat(guild_chat): deck + replay attachments

Implement all five guild_chat attachment endpoints:
- add_deck: server looks up deck by (viewerId, format, deckNo) and snapshots
  the current state into a DECK-type chat message DeckPayload column.
- delete_deck: author OR leader/sub-leader may clear; returns refreshed
  deck_log. Extended IGuildChatMessageRepository.ClearDeckAsync with
  leaderOverride flag; added GetDeckMessagesAsync + GetByMessageIdAsync.
- add_replay: stores {"battle_id": N} in ReplayPayload; full shape is
  TODO(post-merge) pending replay-subsystem capture.
- replay_detail: returns the stored ReplayPayload as JsonElement passthrough.
- deck_log: returns all active DECK messages grouped by API-side Format string
  key ("1"=Rotation, "2"=Unlimited, "3"=PreRotation always present;
  "4"=Crossover, "5"=MyRotation only when non-empty).

Adds DeckLogDataDto (typed) for deck_log / delete_deck responses.
Replay response uses JsonElement passthrough (TODO(post-merge)).
8 new integration tests — all green. Full suite 1530/1530 pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Models/Dtos/GuildChat/GuildChatReplayDetailResponse.cs

@@ -7,13 +7,16 @@ namespace SVSim.EmulatedEntrypoint.Models.Dtos.GuildChat;
 /// <summary>
 /// Response for POST /guild_chat/replay_detail.
 /// Shape is opaque pending replay-subsystem documentation.
-/// TODO(task-17): enumerate fields from Wizard/ReplayDetailInfo.cs when replay subsystem is documented.
+/// TODO(post-merge): enumerate fields from Wizard/ReplayDetailInfo.cs when replay subsystem is documented.
+/// Using JsonElement pass-through so the stored ReplayPayload JSON is forwarded verbatim.
 /// </summary>
 [MessagePackObject]
 public class GuildChatReplayDetailResponse
 {
-    // Placeholder — replay detail shape is undocumented until we capture a live trace.
-    // Using JsonElement pass-through for now.
-    [JsonPropertyName("_todo"), Key("_todo")]
-    public JsonElement? Placeholder { get; set; }
+    /// <summary>
+    /// Opaque replay payload forwarded verbatim from the stored ReplayPayload JSON.
+    /// TODO(post-merge): type this properly once replay subsystem shape is captured.
+    /// </summary>
+    [JsonPropertyName("replay_info"), Key("replay_info")]
+    public JsonElement? ReplayInfo { get; set; }
 }