fix(collections): update window title on collection/document selection

.navigationTitle was hardcoded to the team name and never changed —
the actual macOS window title stayed on the workspace name even with
a collection or document open, while only the custom toolbar pill
updated. Now computed with the same priority so both agree.

Outpost/Features/Collections/ContentView_macOS.swift

@@ -14,6 +14,20 @@ struct ContentView_macOS: View {
         globalSearchQuery.trimmingCharacters(in: .whitespacesAndNewlines)
     }
 
+    /// Mirrors leadingToolbarContent's priority (search > document > collection
+    /// > workspace) so the actual window title and the custom pill agree.
+    private var windowTitle: String {
+        if !trimmedGlobalQuery.isEmpty {
+            return "Search"
+        } else if let currentDocument = documentPath.last {
+            return currentDocument.title.isEmpty ? "Untitled" : currentDocument.title
+        } else if let selectedCollection {
+            return selectedCollection.name
+        } else {
+            return session.teamName ?? "Outpost"
+        }
+    }
+
     var body: some View {
         NavigationSplitView {
             VStack(spacing: 0) {
@@ -26,7 +40,10 @@ struct ContentView_macOS: View {
         } detail: {
             detail
         }
-        .navigationTitle(session.teamName ?? "Outpost")
+        // Was hardcoded to the team name and never updated — the actual macOS
+        // window title (separate from the leadingToolbarContent pill below)
+        // stayed on the workspace name even with a collection/document open.
+        .navigationTitle(windowTitle)
         .toolbar {
             // Per HIG: "sidebar-toggle/back controls appear at the far leading
             // edge, followed by the view title" — this is that title, not