Add a Files tab to the project page

mac/Sources/Byre/Dialogs.swift

@@ -38,6 +38,10 @@ enum LeftTab: String {
     case lead, status, notes, workflows, server, settings
 }
 
+enum ProjectTab {
+    case tasks, files, settings
+}
+
 @MainActor
 @Observable
 final class Overlays {
@@ -53,7 +57,7 @@ final class Overlays {
     var leadFocus = 0
     var tabFocus = 0
     var projectFocus = false
-    var projectSettings = false
+    var projectTab = ProjectTab.tasks
     var taskList = false
     @ObservationIgnored var pickerFrame: CGRect = .zero
     @ObservationIgnored var menuHover = false