Replace toast with Browser Notifications API

- Notifications appear even when user is in other apps/tabs
- Request permission on first stock selection
- Remove Sonner toast dependency from App.tsx

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/App.tsx

@@ -4,7 +4,6 @@ import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs"
 import { Badge } from "@/components/ui/badge"
 import { Toaster } from "@/components/ui/toaster"
-import { Toaster as Sonner, toast } from "@/components/ui/sonner"
 import { TooltipProvider } from "@/components/ui/tooltip"
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query"
 import { BrowserRouter, Routes, Route } from "react-router-dom"
@@ -59,7 +58,6 @@ const App = () => (
   <QueryClientProvider client={queryClient}>
     <TooltipProvider>
       <Toaster />
-      <Sonner />
       <BrowserRouter>
         <Routes>
           <Route path="/" element={<Index />} />
@@ -129,6 +127,24 @@ const Index = () => {
     setUserEvents(prev => [...prev, { timestamp: new Date().toISOString(), message }])
   }
 
+  // Browser Notification helper
+  const notify = (title: string, body: string, type: 'success' | 'error' = 'success') => {
+    if (Notification.permission === 'granted') {
+      new Notification(title, {
+        body,
+        icon: type === 'success' ? '/favicon.ico' : undefined,
+        tag: 'swot-notification', // Prevents duplicate notifications
+      })
+    }
+  }
+
+  // Request notification permission on first stock selection
+  const requestNotificationPermission = () => {
+    if ('Notification' in window && Notification.permission === 'default') {
+      Notification.requestPermission()
+    }
+  }
+
   // Extracted polling logic to avoid duplication
   const startPolling = (workflowIdToUse: string) => {
     if (pollingRef.current) {
@@ -214,11 +230,8 @@ const Index = () => {
           setShowResults(true)
           setMainTab("results")
 
-          // Notify user that report is ready
-          toast.success("Analysis complete!", {
-            description: `SWOT report for ${selectedStock?.symbol || 'company'} is ready.`,
-            duration: 5000
-          })
+          // Notify user that report is ready (works even if tab is in background)
+          notify("Analysis complete!", `SWOT report for ${selectedStock?.symbol || 'company'} is ready.`, 'success')
         } else if (status.status === "aborted") {
           clearInterval(pollingRef.current!)
           pollingRef.current = null
@@ -226,22 +239,16 @@ const Index = () => {
           setIsAborted(true)
           setAbortReason(status.error || 'Critical failure - workflow aborted')
 
-          // Notify user of abort
-          toast.error("Analysis aborted", {
-            description: status.error || "Critical failure - workflow aborted",
-            duration: 8000
-          })
+          // Notify user of abort (works even if tab is in background)
+          notify("Analysis aborted", status.error || "Critical failure - workflow aborted", 'error')
         } else if (status.status === "error") {
           clearInterval(pollingRef.current!)
           pollingRef.current = null
           setIsLoading(false)
           setHasError(true)
 
-          // Notify user of error
-          toast.error("Analysis failed", {
-            description: "An error occurred during analysis.",
-            duration: 8000
-          })
+          // Notify user of error (works even if tab is in background)
+          notify("Analysis failed", "An error occurred during analysis.", 'error')
         }
       } catch (error) {
         console.error("Polling error:", error)
@@ -513,6 +520,7 @@ Generated by Instant SWOT Agent`
                 onSelect={(stock) => {
                   setSelectedStock(stock)
                   addUserEvent(`Selected: ${stock.name} (${stock.symbol})`)
+                  requestNotificationPermission()
                 }}
                 selectedStock={selectedStock}
                 onClear={handleStockClear}