feat(files): add per-channel storage quota [CI]

server/src/WebDrop.Core/Workspace.cs

@@ -8,6 +8,7 @@ public sealed class WorkspaceChannel
     [JsonPropertyName("filesEpoch")] public int FilesEpoch { get; set; }
     [JsonPropertyName("chatHistory")] public bool ChatHistory { get; set; } = true;
     [JsonPropertyName("filesHistory")] public bool FilesHistory { get; set; } = true;
+    [JsonPropertyName("fileBytes")] public long FileBytes { get; set; }
     [JsonPropertyName("id")] public required string Id { get; init; }
     [JsonPropertyName("name")] public required string Name { get; set; }
     [JsonPropertyName("createdAt")] public required long CreatedAt { get; init; }