Add global navigation to MCP browse_screens response

Adds globalNav array to every browse_screens response with links to:
- My Notifications (apps/my/User/Notifications)
- My Messages (apps/my/User/Messages/FindMessage)
- My Calendar (apps/my/User/Calendar/MyCalendar)
- My Tasks (apps/my/User/Task/MyTasks)

These mirror the MyAccountNav component in the web UI and are always
available regardless of which app the user is currently browsing.

Also adds a hint in uiNarrative.notes about globalNav and search.

@@ -2450,6 +2450,15 @@ def wikiInstructions = getWikiInstructions(inputScreenPath)
                     renderMode: actualRenderMode
                 ]
                 
+                // Add global navigation - these are always available regardless of current app
+                // Mirrors the MyAccountNav component in the web UI
+                resultMap.globalNav = [
+                    [name: "My Notifications", path: "apps/my/User/Notifications", icon: "info"],
+                    [name: "My Messages", path: "apps/my/User/Messages/FindMessage", icon: "message"],
+                    [name: "My Calendar", path: "apps/my/User/Calendar/MyCalendar", icon: "calendar"],
+                    [name: "My Tasks", path: "apps/my/User/Task/MyTasks", icon: "tasks"]
+                ]
+
                 if (currentPath != "root") {
                     try {
                         ec.logger.info("BrowseScreens: Rendering screen ${currentPath} with mode=${actualRenderMode}")

@@ -251,6 +251,9 @@ class UiNarrativeBuilder {
             }
         }
         
+        // Hint about global nav and search
+        notes << "Global nav (Messages, Tasks, Calendar, Notifications) available in response.globalNav. Use moqui_search_screens(query='...') to find other screens."
+        
         return notes
     }