fix(library): preserve explorer column choices across restarts

Store browser searches and facet selections per profile with atomic writes. Prefer navigation history when available and restore saved choices before QML can publish construction defaults. Keep the startup crash guard and unrelated preferences intact.

Validate with six QML audits and two passing profile-isolation and persistence regressions.

cx

crates/qbz-qt/qml/views/LocalLibraryView.qml

@@ -165,6 +165,7 @@ Rectangle {
     // this document restores the controls that determine what that offset
     // means before the tab asks for data.
     property bool _restoringNavigationState: false
+    property bool _navigationReady: false
     readonly property string navigationStateJson: JSON.stringify({
         activeTab: root.activeTab,
         albumsSearch: root.albumsSearch,
@@ -203,14 +204,16 @@ Rectangle {
         genresSort: root.genresSort
     })
     onNavigationStateJsonChanged: {
-        if (!root._restoringNavigationState && QbzShell.currentView === "local")
+        if (root._navigationReady && !root._restoringNavigationState
+                && QbzShell.currentView === "local")
             QbzShell.reportNavState("local", root.navigationStateJson)
     }
     function restoreNavigationState() {
-        if (QbzShell.restoreStateScope !== "local" || QbzShell.stateRestore === "")
-            return
+        var state = QbzShell.restoreStateScope === "local" && QbzShell.stateRestore !== ""
+            ? QbzShell.stateRestore : QbzShell.localNavigationState()
+        if (state === "") return
         var saved
-        try { saved = JSON.parse(QbzShell.stateRestore) }
+        try { saved = JSON.parse(state) }
         catch (e) { QbzShell.restoreStateScope = ""; return }
         root._restoringNavigationState = true
         function text(name, fallback) {
@@ -654,6 +657,7 @@ Rectangle {
     // one query; the Albums/Folders/Artists sets are bounded).
     Component.onCompleted: {
         restoreNavigationState()
+        root._navigationReady = true
         // Initial bindings are not a reliable change notification contract:
         // explicitly seed history even when this is a fresh entry whose state
         // happens to equal every default.