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.UnitTests/Wire/GuildWireShape.cs

@@ -0,0 +1,40 @@
+using NUnit.Framework;
+using System.Text.Json;
+using SVSim.EmulatedEntrypoint.Models.Dtos.Guild;
+
+namespace SVSim.UnitTests.Wire;
+
+[TestFixture]
+public class GuildWireShape
+{
+    private static readonly JsonSerializerOptions Opts = new()
+    {
+        PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
+        DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull,
+    };
+
+    [Test]
+    public void GuildInfo_non_joined_serializes_to_prod_shape()
+    {
+        var resp = new GuildInfoResponse
+        {
+            MaxMemberNum = 30,
+            MaxSubLeaderNum = 2,
+            GuildStatus = 0,
+            UsableStampList = Enumerable.Range(100001, 20).Select(i => i.ToString()).ToList(),
+        };
+        var json = JsonSerializer.Serialize(resp, Opts);
+        using var doc = JsonDocument.Parse(json);
+        var root = doc.RootElement;
+
+        Assert.That(root.GetProperty("max_member_num").GetString(), Is.EqualTo("30"));
+        Assert.That(root.GetProperty("max_sub_leader_num").GetString(), Is.EqualTo("2"));
+        Assert.That(root.GetProperty("guild_status").GetString(), Is.EqualTo("0"));
+        Assert.That(root.GetProperty("usable_stamp_list").EnumerateArray().Select(e => e.GetString()).First(), Is.EqualTo("100001"));
+
+        // The four nullable fields MUST NOT appear when null:
+        Assert.That(root.TryGetProperty("guild", out _), Is.False);
+        Assert.That(root.TryGetProperty("join_request_count", out _), Is.False);
+        Assert.That(root.TryGetProperty("invite_count", out _), Is.False);
+    }
+}