feat: Implement recursive storage listing and directory browsing for backups, and add a migration option to fix cross-filters.

frontend/src/routes/settings/+page.svelte

@@ -65,7 +65,15 @@
   };
 
   function normalizeTab(value) {
-    return SETTINGS_TABS.includes(value) ? value : "environments";
+    const normalized = String(value || "").trim().toLowerCase();
+    const aliases = {
+      environment: "environments",
+      env: "environments",
+      "migration-sync": "migration",
+      storages: "storage",
+    };
+    const resolved = aliases[normalized] || normalized;
+    return SETTINGS_TABS.includes(resolved) ? resolved : "environments";
   }
 
   function readTabFromUrl() {
@@ -89,8 +97,17 @@
   // Load settings on mount
   onMount(async () => {
     activeTab = readTabFromUrl();
+    const syncTabFromUrl = () => {
+      activeTab = readTabFromUrl();
+    };
+    window.addEventListener("popstate", syncTabFromUrl);
+    window.addEventListener("hashchange", syncTabFromUrl);
     await loadSettings();
     await loadMigrationSettings();
+    return () => {
+      window.removeEventListener("popstate", syncTabFromUrl);
+      window.removeEventListener("hashchange", syncTabFromUrl);
+    };
   });
 
   // Load consolidated settings from API
@@ -163,9 +180,10 @@
 
   // Handle tab change
   function handleTabChange(tab) {
-    activeTab = normalizeTab(tab);
+    const normalizedTab = normalizeTab(tab);
+    activeTab = normalizedTab;
     writeTabToUrl(activeTab);
-    if (tab === "migration") {
+    if (normalizedTab === "migration") {
       loadMigrationSettings();
     }
   }