fix: only promote live panel titles to the workspace title

Sources/Workspace+Persistence.swift

@@ -471,6 +471,7 @@ extension Workspace {
     private func applySessionPanelMetadata(_ snapshot: SessionPanelSnapshot, toPanelId panelId: UUID) {
         if let title = snapshot.title?.trimmingCharacters(in: .whitespacesAndNewlines), !title.isEmpty {
             panelTitles[panelId] = title
+            panelsWithLiveTitle.insert(panelId)
         }
 
         setPanelCustomTitle(panelId: panelId, title: snapshot.customTitle)

Sources/Workspace+SidebarTelemetry.swift

@@ -219,6 +219,7 @@ extension Workspace {
             panelTitles[panelId] = trimmed
             didMutate = true
         }
+        panelsWithLiveTitle.insert(panelId)
 
         // Update bonsplit tab title only when this panel's title changed.
         if didMutate,
@@ -251,10 +252,13 @@ extension Workspace {
 
     /// Re-derive the workspace title from the focused panel's last known
     /// title. Called on pane-focus changes so the sidebar follows the active
-    /// pane without waiting for it to emit a new OSC title.
+    /// pane without waiting for it to emit a new OSC title. Only titles that
+    /// arrived through a real update qualify; creation-time displayTitle
+    /// seeds must not overwrite the workspace's default title.
     func refreshWorkspaceTitleFromFocusedPanel() {
         guard customTitle == nil,
               let panelId = focusedPanelId,
+              panelsWithLiveTitle.contains(panelId),
               let stored = panelTitles[panelId] else { return }
         if title != stored { title = stored }
         if processTitle != stored { processTitle = stored }
@@ -263,6 +267,7 @@ extension Workspace {
     func pruneSurfaceMetadata(validSurfaceIds: Set<UUID>) {
         panelDirectories = panelDirectories.filter { validSurfaceIds.contains($0.key) }
         panelTitles = panelTitles.filter { validSurfaceIds.contains($0.key) }
+        panelsWithLiveTitle = panelsWithLiveTitle.filter { validSurfaceIds.contains($0) }
         panelCustomTitles = panelCustomTitles.filter { validSurfaceIds.contains($0.key) }
         pinnedPanelIds = pinnedPanelIds.filter { validSurfaceIds.contains($0) }
         manualUnreadPanelIds = manualUnreadPanelIds.filter { validSurfaceIds.contains($0) }

Sources/Workspace.swift

@@ -84,6 +84,10 @@ final class Workspace: Identifiable, ObservableObject {
     /// Published directory for each panel
     @Published var panelDirectories: [UUID: String] = [:]
     @Published var panelTitles: [UUID: String] = [:]
+    /// Panels whose `panelTitles` entry came from a real title update (OSC or
+    /// session restore), as opposed to the displayTitle placeholder seeded at
+    /// panel creation. Only these titles may be promoted to the workspace title.
+    var panelsWithLiveTitle: Set<UUID> = []
     @Published var panelCustomTitles: [UUID: String] = [:]
     @Published var pinnedPanelIds: Set<UUID> = []
     @Published var manualUnreadPanelIds: Set<UUID> = []