feat(guild): controller scaffolding + /guild/info baseline

- 5 common DTOs under Models/Dtos/Common/Guild/ (GuildDetailDto,
  GuildUserBaseDto, GuildMemberInfoDto, ChatUserDto, ChatMessageDto)
- 28 per-endpoint request/response DTOs under Models/Dtos/Guild/ and
  Models/Dtos/GuildChat/ with full [MessagePackObject]/[Key]/
  [JsonPropertyName] attribute mirrors on every property
- GuildController (22 actions): /guild/info returns prod-shape with
  config-backed max_member_num/max_sub_leader_num/usable_stamp_list;
  21 stubs return empty/default DTOs
- GuildChatController (7 stubs), /guild_chat/messages stub returns
  wait_interval=10 per config
- 29 new routing smoke test cases (100 total, all pass)
- GuildWireShape literal-JSON test for GuildInfoResponse (1/1 pass)
- GameConfigurationJsonbTests updated for 17th GuildConfig section
- Total: 1422 tests pass, 0 errors

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

SVSim.EmulatedEntrypoint/Models/Dtos/Common/Guild/ChatUserDto.cs

@@ -0,0 +1,39 @@
+using MessagePack;
+using System.Text.Json.Serialization;
+using SVSim.EmulatedEntrypoint.Models.Dtos.Common;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.Common.Guild;
+
+/// <summary>
+/// Generic UserInfoBase shape for chat contexts — used in /guild_chat/messages `users[]`
+/// and shared with /gathering_chat. Matches types.ts.md#user-profile-types ChatUser (UserInfoBase).
+/// </summary>
+[MessagePackObject]
+public class ChatUserDto
+{
+    [JsonPropertyName("viewer_id"), Key("viewer_id"), JsonConverter(typeof(StringifiedLongConverter))]
+    public long ViewerId { get; set; }
+
+    [JsonPropertyName("name"), Key("name")]
+    public string Name { get; set; } = "";
+
+    [JsonPropertyName("emblem_id"), Key("emblem_id"), JsonConverter(typeof(StringifiedLongConverter))]
+    public long EmblemId { get; set; }
+
+    [JsonPropertyName("country_code"), Key("country_code")]
+    public string CountryCode { get; set; } = "";
+
+    [JsonPropertyName("rank"), Key("rank"), JsonConverter(typeof(StringifiedIntConverter))]
+    public int Rank { get; set; }
+
+    [JsonPropertyName("degree_id"), Key("degree_id"), JsonConverter(typeof(StringifiedIntConverter))]
+    public int DegreeId { get; set; }
+
+    /// <summary>Optional — omit when the viewer has no friend relationship with this user.</summary>
+    [JsonPropertyName("is_friend"), Key("is_friend")]
+    public int? IsFriend { get; set; }
+
+    /// <summary>Optional — omit when no pending friend apply.</summary>
+    [JsonPropertyName("is_friend_apply"), Key("is_friend_apply")]
+    public int? IsFriendApply { get; set; }
+}