Fix Nav tab infinite recursion (pre-UX-sweep bug)

The reverted code had two bugs in the tab switching logic:
1. closeNavigate() called switchTab() -> infinite recursion since
   switchTab() calls closeNavigate() when leaving tabNavigate
2. currentTab was updated AFTER closeNavigate(), so the recursive
   call hit the same condition over and over

Fix: move currentTab assignment before cleanup, use a wasNavigating
flag to track the old tab state, and make closeNavigate() only reset
nav UI (caller handles tab transition).

static/index.html

@@ -2339,15 +2339,19 @@
     // TAB SWITCHING
     // =========================================================================
     function switchTab(tabId) {
+      const wasNavigating = AppState.currentTab === 'tabNavigate';
       // Track previous tab for back navigation
-      if (AppState.currentTab !== tabId && AppState.currentTab !== 'tabNavigate') {
+      if (AppState.currentTab !== tabId && !wasNavigating) {
         AppState._prevTab = AppState.currentTab;
       }
-      // Cleanup nav page when leaving
+      // Update current tab BEFORE cleanup to prevent recursion
-      if (AppState.currentTab === 'tabNavigate' && tabId !== 'tabNavigate') {
+      // when closeNavigate() calls switchTab()
+      AppState.currentTab = tabId;
+      // Cleanup nav page when leaving (closeNavigate only resets nav state,
+      // it does NOT switch panels — we must NOT return early here)
+      if (wasNavigating && tabId !== 'tabNavigate') {
         closeNavigate();
       }
-      AppState.currentTab = tabId;
 
       // Update tab panels
       document.querySelectorAll('.tab-panel').forEach(p => p.classList.remove('active'));
@@ -3681,8 +3685,13 @@
     function closeNavigate() {
       if (navMap) { navMap.remove(); navMap = null; }
       AppState._navData = null;
-      // Go back to previous tab or asset list
+      // Reset navigate tab UI — does NOT switch tabs, caller handles that
-      switchTab(AppState._prevTab || 'tabAssets');
+      const infoCard = document.getElementById('navInfoCard');
+      if (infoCard) infoCard.style.display = 'none';
+      const directionsCard = document.getElementById('navDirectionsCard');
+      if (directionsCard) directionsCard.style.display = 'none';
+      const gmapsLink = document.getElementById('navGoogleMapsLink');
+      if (gmapsLink) gmapsLink.style.display = 'none';
     }
 
     function clearRouteLine() {