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/GuildChatDeckLogResponse.cs

@@ -1,14 +1,15 @@
 using MessagePack;
-using System.Text.Json;
 using System.Text.Json.Serialization;
+using SVSim.EmulatedEntrypoint.Models.Dtos.Common;
+using SVSim.EmulatedEntrypoint.Models.Dtos.Common.Guild;
 
 namespace SVSim.EmulatedEntrypoint.Models.Dtos.GuildChat;
 
 /// <summary>
 /// Response for POST /guild_chat/deck_log.
-/// deck_log keys are stringified API-side Format ints (e.g. "1", "2").
-/// TODO(task-17): replace deck_log with typed DTOs when DeckLogData shape is fully specified.
-/// Crossover/MyRotation keys must be OMITTED (not empty arrays) when those formats are disabled.
+/// deck_log keys are stringified API-side Format ints (e.g. "1", "2", "3").
+/// Rotation / Unlimited / PreRotation buckets are always present.
+/// Crossover / MyRotation keys are included only when non-empty (client uses TryGetValue).
 /// </summary>
 [MessagePackObject]
 public class GuildChatDeckLogResponse
@@ -19,8 +20,9 @@ public class GuildChatDeckLogResponse
 
     /// <summary>
     /// Decks shared in chat, bucketed by API-side Format value (stringified int keys).
-    /// JsonElement pass-through for now — Task 17 will type the inner DeckLogEntry shape.
+    /// Keys present: "1" (Rotation), "2" (Unlimited), "3" (PreRotation); optionally "4" (Crossover), "5" (MyRotation).
     /// </summary>
-    [JsonPropertyName("deck_log"), Key("deck_log")]
-    public JsonElement? DeckLog { get; set; }
+    [JsonPropertyName("deck_log"), Key("deck_log"),
+     JsonIgnore(Condition = JsonIgnoreCondition.Never)]
+    public Dictionary<string, List<DeckLogDataDto>> DeckLog { get; set; } = new();
 }

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

@@ -1,13 +1,13 @@
 using MessagePack;
-using System.Text.Json;
 using System.Text.Json.Serialization;
+using SVSim.EmulatedEntrypoint.Models.Dtos.Common;
+using SVSim.EmulatedEntrypoint.Models.Dtos.Common.Guild;
 
 namespace SVSim.EmulatedEntrypoint.Models.Dtos.GuildChat;
 
 /// <summary>
 /// Response for POST /guild_chat/delete_deck.
-/// Returns refreshed deck_log after deletion.
-/// TODO(task-17): replace deck_log with typed DeckLogData DTOs when deck-log shape is fully documented.
+/// Returns the refreshed deck_log after deletion — same shape as /guild_chat/deck_log.
 /// </summary>
 [MessagePackObject]
 public class GuildChatDeleteDeckResponse
@@ -17,9 +17,10 @@ public class GuildChatDeleteDeckResponse
     public List<int> MaintenanceCardList { get; set; } = new();
 
     /// <summary>
-    /// Refreshed deck log keyed by API-side Format int (stringified, e.g. "1", "2").
-    /// Using JsonElement for now; Task 17 will type this properly.
+    /// Refreshed deck log keyed by API-side Format int (stringified, e.g. "1", "2", "3").
+    /// Crossover ("4") / MyRotation ("5") included only when non-empty.
     /// </summary>
-    [JsonPropertyName("deck_log"), Key("deck_log")]
-    public JsonElement? DeckLog { get; set; }
+    [JsonPropertyName("deck_log"), Key("deck_log"),
+     JsonIgnore(Condition = JsonIgnoreCondition.Never)]
+    public Dictionary<string, List<DeckLogDataDto>> DeckLog { get; set; } = new();
 }

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; }
 }