fix(guild): final-review remediation — replay_detail flat, FK on leader, transaction wraps, _db extraction

C1: replay_detail — flatten stored payload to data level. ChatReplayDetailTask.Parse() calls
new ReplayDetailInfo(data) which unguardedly accesses data[battleId], data[seed], data[vid1],
etc. Wrapping under replay_info key crashes the client. Controller now returns Ok(JsonElement)
directly so stored battle fields are at data root. Wire-shape test added.

C2: Guild.LeaderViewerId long to long?; add HasOne<Viewer> FK with OnDelete=SetNull; migration
AddGuildLeaderViewerIdFk; all consumers null-guarded with ?? 0L.

C3: BreakupAsync — wrap 6 destructive ops in IDbContextTransaction with InMemory fallback.

C4: CommitJoinAsync — wrap member-add + viewer-guildId-set + invite/request cleanup in
IDbContextTransaction with InMemory fallback. Chat event emitted after commit.

I1: GuildController — remove SVSimDbContext field; inject IViewerRepository + IGuildMemberRepository.
Add IGuildMemberRepository.GetViewerIdsInAGuildAsync (batch guild-membership check).
All _db.Viewers / _db.GuildMembers queries replaced with repo calls.

I2: GuildService — extract 3 _db.Viewers queries: GetEquippedEmblemIdAsync (CreateAsync),
LoadGuildProfileBatchAsync (ListOutgoingInvitesAsync + ListPendingJoinRequestsForMyGuildAsync).
Add GuildMemberProfile record with IsOfficialMarkDisplayed. GetEmblemListAsync for EmblemList.

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

SVSim.Database/Repositories/Guild/GuildMemberRepository.cs

@@ -70,4 +70,15 @@ public sealed class GuildMemberRepository : IGuildMemberRepository
             result[row.GuildId] = row.Count;
         return result;
     }
+
+    public async Task<HashSet<long>> GetViewerIdsInAGuildAsync(
+        IReadOnlyList<long> viewerIds, CancellationToken ct = default)
+    {
+        if (viewerIds.Count == 0) return new HashSet<long>();
+        var ids = await _db.GuildMembers
+            .Where(m => viewerIds.Contains(m.ViewerId))
+            .Select(m => m.ViewerId)
+            .ToListAsync(ct);
+        return new HashSet<long>(ids);
+    }
 }

SVSim.Database/Repositories/Guild/IGuildMemberRepository.cs

@@ -15,4 +15,11 @@ public interface IGuildMemberRepository
 
     /// <summary>Returns a count of members per guild for the given guild ids. Used by Task 9 search.</summary>
     Task<Dictionary<int, int>> CountBatchByGuildIdsAsync(IReadOnlyList<int> guildIds, CancellationToken ct = default);
+
+    /// <summary>
+    /// Batch-checks whether each viewer id in <paramref name="viewerIds"/> is currently in any guild.
+    /// Returns a set of viewer ids that ARE in a guild. Used by <c>/guild/friend_list</c> to set
+    /// <c>is_join_guild</c>.
+    /// </summary>
+    Task<HashSet<long>> GetViewerIdsInAGuildAsync(IReadOnlyList<long> viewerIds, CancellationToken ct = default);
 }

SVSim.Database/Repositories/Viewer/IViewerRepository.cs

@@ -13,6 +13,18 @@ public record ChatUserProfile(
     int    Rank,
     int    DegreeId);
 
+/// <summary>
+/// Richer profile shape used by guild management surfaces (invite list, join-request list).
+/// Extends <see cref="ChatUserProfile"/> with <c>IsOfficialMarkDisplayed</c>.
+/// </summary>
+public record GuildMemberProfile(
+    string Name,
+    long   EmblemId,
+    string CountryCode,
+    int    Rank,
+    int    DegreeId,
+    bool   IsOfficialMarkDisplayed);
+
 public interface IViewerRepository
 {
     Task<Models.Viewer?> GetViewerBySocialConnection(SocialAccountType accountType, ulong socialId);
@@ -57,4 +69,23 @@ public interface IViewerRepository
     /// in the controller. Ids with no matching row are absent from the result. Read-only (AsNoTracking).
     /// </summary>
     Task<IReadOnlyDictionary<long, ChatUserProfile>> LoadChatProfilesAsync(IReadOnlyCollection<long> viewerIds, CancellationToken ct = default);
+
+    /// <summary>
+    /// Batch-loads the <see cref="GuildMemberProfile"/> fields (emblem, degree,
+    /// <c>IsOfficialMarkDisplayed</c>) for a set of viewer ids. Used by guild management surfaces
+    /// (invite_user_list, join_request_list). Ids with no matching row are absent. Read-only.
+    /// </summary>
+    Task<IReadOnlyDictionary<long, GuildMemberProfile>> LoadGuildProfileBatchAsync(IReadOnlyCollection<long> viewerIds, CancellationToken ct = default);
+
+    /// <summary>
+    /// Loads a viewer's currently-equipped emblem id, or <c>100_000_000</c> (default) if none.
+    /// Used by <see cref="SVSim.Database.Services.Guild.GuildService"/> to seed the guild's initial emblem.
+    /// Returns <c>100_000_000</c> if the viewer doesn't exist.
+    /// </summary>
+    Task<long> GetEquippedEmblemIdAsync(long viewerId, CancellationToken ct = default);
+
+    /// <summary>
+    /// Batch-loads owned guild-emblem ids for a viewer. Used by <c>/guild/emblem_list</c>.
+    /// </summary>
+    Task<List<long>> GetEmblemListAsync(long viewerId, CancellationToken ct = default);
 }

SVSim.Database/Repositories/Viewer/ViewerRepository.cs

@@ -323,6 +323,56 @@ public class ViewerRepository : IViewerRepository
                 DegreeId:    r.DegreeId));
     }
 
+    public async Task<IReadOnlyDictionary<long, GuildMemberProfile>> LoadGuildProfileBatchAsync(IReadOnlyCollection<long> viewerIds, CancellationToken ct = default)
+    {
+        if (viewerIds.Count == 0) return new Dictionary<long, GuildMemberProfile>();
+        var rows = await _dbContext.Set<Models.Viewer>()
+            .AsNoTracking()
+            .Include(v => v.Info.SelectedEmblem)
+            .Include(v => v.Info.SelectedDegree)
+            .Where(v => viewerIds.Contains(v.Id))
+            .Select(v => new
+            {
+                v.Id,
+                v.DisplayName,
+                EmblemId               = v.Info.SelectedEmblem != null ? v.Info.SelectedEmblem.Id : 100_000_000L,
+                CountryCode            = v.Info.CountryCode ?? "",
+                DegreeId               = v.Info.SelectedDegree != null ? (int)v.Info.SelectedDegree.Id : 0,
+                IsOfficialMarkDisplayed = v.Info.IsOfficialMarkDisplayed,
+            })
+            .ToListAsync(ct);
+        return rows.ToDictionary(
+            r => r.Id,
+            r => new GuildMemberProfile(
+                Name:                   r.DisplayName,
+                EmblemId:               r.EmblemId,
+                CountryCode:            r.CountryCode,
+                Rank:                   1, // TODO: real rank when rank tracking lands
+                DegreeId:               r.DegreeId,
+                IsOfficialMarkDisplayed: r.IsOfficialMarkDisplayed));
+    }
+
+    public async Task<long> GetEquippedEmblemIdAsync(long viewerId, CancellationToken ct = default)
+    {
+        var row = await _dbContext.Set<Models.Viewer>()
+            .AsNoTracking()
+            .Include(v => v.Info.SelectedEmblem)
+            .Where(v => v.Id == viewerId)
+            .Select(v => new { EmblemId = v.Info.SelectedEmblem != null ? v.Info.SelectedEmblem.Id : 100_000_000L })
+            .FirstOrDefaultAsync(ct);
+        return row?.EmblemId ?? 100_000_000L;
+    }
+
+    public async Task<List<long>> GetEmblemListAsync(long viewerId, CancellationToken ct = default)
+    {
+        var viewer = await _dbContext.Set<Models.Viewer>()
+            .AsNoTracking()
+            .Include(v => v.Emblems)
+            .Where(v => v.Id == viewerId)
+            .FirstOrDefaultAsync(ct);
+        return viewer?.Emblems.Select(e => (long)e.Id).ToList() ?? new List<long>();
+    }
+
     private async Task<Models.Viewer> BuildDefaultViewer(string displayName, int initialTutorialState = 1)
     {
         Models.Viewer viewer = new Models.Viewer