Add risk center and editable submission flows

Backend/Domain/AdminAuditEntry.cs

@@ -0,0 +1,13 @@
+namespace Backend.Domain;
+
+public sealed class AdminAuditEntry
+{
+    public int Id { get; set; }
+    public string AdminTwitchUserId { get; set; } = string.Empty;
+    public string ActionType { get; set; } = string.Empty;
+    public string EntityType { get; set; } = string.Empty;
+    public string EntityId { get; set; } = string.Empty;
+    public string Summary { get; set; } = string.Empty;
+    public string MetadataJson { get; set; } = "{}";
+    public DateTimeOffset CreatedAt { get; set; }
+}

Backend/Domain/RiskFlag.cs

@@ -0,0 +1,20 @@
+namespace Backend.Domain;
+
+public sealed class RiskFlag
+{
+    public int Id { get; set; }
+    public int? SeasonId { get; set; }
+    public Season? Season { get; set; }
+    public string? TwitchUserId { get; set; }
+    public string Source { get; set; } = string.Empty;
+    public string Type { get; set; } = string.Empty;
+    public string Severity { get; set; } = "medium";
+    public string Status { get; set; } = "open";
+    public string Summary { get; set; } = string.Empty;
+    public string CreatedFromIp { get; set; } = string.Empty;
+    public string UserAgent { get; set; } = string.Empty;
+    public string MetadataJson { get; set; } = "{}";
+    public string? ReviewedByTwitchId { get; set; }
+    public DateTimeOffset CreatedAt { get; set; }
+    public DateTimeOffset? ReviewedAt { get; set; }
+}

Backend/Domain/UserSession.cs

@@ -7,6 +7,8 @@ public sealed class UserSession
     public string TwitchUserId { get; set; } = string.Empty;
     public string DisplayName { get; set; } = string.Empty;
     public string Role { get; set; } = "viewer";
+    public string CreatedFromIp { get; set; } = string.Empty;
+    public string UserAgent { get; set; } = string.Empty;
     public DateTimeOffset CreatedAt { get; set; }
     public DateTimeOffset LastSeenAt { get; set; }
     public bool IsActive { get; set; }