feat(backend): add support conversations

Foxnouns.Backend/Database/Models/SupportConversation.cs

@@ -0,0 +1,19 @@
+namespace Foxnouns.Backend.Database.Models;
+
+public class SupportConversation : BaseModel
+{
+    public Snowflake UserId { get; init; }
+    public User User { get; init; } = null!;
+    public required string Title { get; set; }
+    public Snowflake? AssignedToId { get; set; }
+    public User? AssignedTo { get; set; }
+
+    public SupportConversationStatus Status { get; set; } = SupportConversationStatus.Open;
+}
+
+public enum SupportConversationStatus
+{
+    Open,
+    Resolved,
+    Closed,
+}

Foxnouns.Backend/Database/Models/SupportMessage.cs

@@ -0,0 +1,30 @@
+using NodaTime;
+
+namespace Foxnouns.Backend.Database.Models;
+
+public class SupportMessage : BaseModel
+{
+    public Snowflake ConversationId { get; init; }
+    public SupportConversation Conversation { get; init; } = null!;
+    public Snowflake UserId { get; init; }
+    public User User { get; init; } = null!;
+    public bool IsAnonymous { get; init; }
+
+    public string? Content { get; set; }
+
+    public List<Attachment> Attachments { get; set; } = [];
+    public List<HistoryEntry> History { get; set; } = [];
+
+    public class Attachment
+    {
+        public required Snowflake Id { get; init; }
+        public required string Hash { get; init; }
+        public required string ContentType { get; init; }
+    }
+
+    public class HistoryEntry
+    {
+        public required Instant Timestamp { get; init; }
+        public required string? Content { get; init; }
+    }
+}