Fix status bar not updating when workspace is first opened

The status bar cursor position label relied solely on tabBarTabIdSubject
(a PassthroughSubject) and onAppear to get the current tab. When a workspace
was first opened, the selected tab was set during state restoration before the
status bar view subscribed to the subject, causing it to miss the initial value.

This adds an additional onReceive subscriber to the active editor's
$selectedTab publisher, which is a @published property and replays its current
value on subscription, ensuring the status bar updates immediately.

Fixes #1729

Author: William-Laverty

CodeEdit/Features/StatusBar/Views/StatusBarItems/StatusBarCursorPositionLabel.swift

@@ -38,6 +38,9 @@ struct StatusBarCursorPositionLabel: View {
         .onReceive(editorManager.tabBarTabIdSubject) { _ in
             updateSource()
         }
+        .onReceive(editorManager.activeEditor.$selectedTab) { _ in
+            updateSource()
+        }
     }
 
     struct LineLabel: View {