fix(guild): populate leader_name in search results (matches prod capture)

Add IViewerRepository.LoadDisplayNamesAsync (batch AsNoTracking select),
extend GuildSearchEntry with LeaderName, enrich GuildService.SearchAsync
with a leader-id batch lookup, and thread the name through the controller's
ToDetailDto call. Adds a leader_name assertion to GuildSearchFlowTests.

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

SVSim.Database/Repositories/Viewer/IViewerRepository.cs

@@ -33,4 +33,10 @@ public interface IViewerRepository
 
     /// <summary>Clears Viewer.GuildId to null. No-op if the viewer does not exist.</summary>
     Task ClearGuildIdAsync(long viewerId, CancellationToken ct = default);
+
+    /// <summary>
+    /// Batch-loads <c>DisplayName</c> for a set of viewer ids. Returns a dictionary keyed by viewer id;
+    /// ids with no matching row are absent from the result. Read-only (AsNoTracking).
+    /// </summary>
+    Task<Dictionary<long, string>> LoadDisplayNamesAsync(IReadOnlyCollection<long> viewerIds, CancellationToken ct = default);
 }

SVSim.Database/Repositories/Viewer/ViewerRepository.cs

@@ -286,6 +286,16 @@ public class ViewerRepository : IViewerRepository
         await _dbContext.SaveChangesAsync(ct);
     }
 
+    public async Task<Dictionary<long, string>> LoadDisplayNamesAsync(IReadOnlyCollection<long> viewerIds, CancellationToken ct = default)
+    {
+        if (viewerIds.Count == 0) return new Dictionary<long, string>();
+        return await _dbContext.Set<Models.Viewer>()
+            .AsNoTracking()
+            .Where(v => viewerIds.Contains(v.Id))
+            .Select(v => new { v.Id, v.DisplayName })
+            .ToDictionaryAsync(v => v.Id, v => v.DisplayName, ct);
+    }
+
     private async Task<Models.Viewer> BuildDefaultViewer(string displayName, int initialTutorialState = 1)
     {
         Models.Viewer viewer = new Models.Viewer

SVSim.Database/Services/Guild/GuildService.cs

@@ -65,8 +65,11 @@ public sealed class GuildService : IGuildService
     {
         var cfg = _config.Get<GuildConfig>();
         var rows = await _guilds.SearchAsync(name ?? "", activity, joinCondition, memberBucket, cfg.MaxMemberNum, cfg.SearchResultCap, ct);
-        var memberCounts = await _members.CountBatchByGuildIdsAsync(rows.Select(r => r.GuildId).ToList(), ct);
-        return rows.Select(r => new GuildSearchEntry(r, memberCounts.GetValueOrDefault(r.GuildId, 0))).ToList();
+        var guildIds = rows.Select(r => r.GuildId).ToList();
+        var memberCounts = await _members.CountBatchByGuildIdsAsync(guildIds, ct);
+        var leaderIds = rows.Select(r => r.LeaderViewerId).Distinct().ToList();
+        var leaderNames = await _viewers.LoadDisplayNamesAsync(leaderIds, ct);
+        return rows.Select(r => new GuildSearchEntry(r, memberCounts.GetValueOrDefault(r.GuildId, 0), leaderNames.GetValueOrDefault(r.LeaderViewerId, ""))).ToList();
     }
 
     public async Task<GuildOpResult> CreateAsync(long viewerId, CreateGuildRequest req, CancellationToken ct = default)

SVSim.Database/Services/Guild/GuildServiceTypes.cs

@@ -34,7 +34,7 @@ public sealed record GuildFullView(
     int JoinRequestCount,
     int InviteCount);
 
-public sealed record GuildSearchEntry(Entities.Guild.Guild Guild, int MemberNum);
+public sealed record GuildSearchEntry(Entities.Guild.Guild Guild, int MemberNum, string LeaderName);
 
 public sealed record CreateGuildRequest(string Name, int Activity, int JoinCondition);
 public sealed record UpdateGuildRequest(int? Activity, int? JoinCondition, string? Name = null);

SVSim.EmulatedEntrypoint/Controllers/GuildController.cs

@@ -135,7 +135,7 @@ public sealed class GuildController : SVSimController
     {
         if (!TryGetViewerId(out var v)) return Unauthorized();
         var entries = await _guild.SearchAsync(req.GuildName ?? "", req.Activity, req.JoinCondition, req.MemberConditionRange, ct);
-        return new GuildSearchGuildResponse { List = entries.Select(e => ToDetailDto(e.Guild, e.MemberNum)).ToList() };
+        return new GuildSearchGuildResponse { List = entries.Select(e => ToDetailDto(e.Guild, e.MemberNum, e.LeaderName)).ToList() };
     }
 
     [HttpPost("emblem_list")]

SVSim.UnitTests/Integration/Guild/GuildSearchFlowTests.cs

@@ -231,5 +231,8 @@ public class GuildSearchFlowTests
         Assert.That(entry.TryGetProperty("detail", out _), Is.False, "no 'detail' wrapper on search list entries");
         Assert.That(entry.TryGetProperty("guild_name", out var gn), Is.True);
         Assert.That(gn.GetString(), Is.EqualTo("SmallFreeGuild"));
+        // leader_name must be populated from the seeded viewer's DisplayName, not empty string
+        Assert.That(entry.TryGetProperty("leader_name", out var ln), Is.True, "leader_name field must be present");
+        Assert.That(ln.GetString(), Is.EqualTo("SearchLeader7"), "leader_name must match the seeded leader's DisplayName");
     }
 }