feat: v0.17.0 — ISS-008 toasts for errors/events + browser notifications

app/globals.css

@@ -347,3 +347,70 @@ body {
   padding: 6px 0 0;
   border-top: 1px solid rgba(148, 163, 184, 0.2);
 }
+
+/* v0.17.0 — ISS-008: bottom-right toast stack (action errors + game events) */
+.toasts {
+  position: fixed;
+  bottom: 12px;
+  right: 12px;
+  z-index: 50; /* above map popups/controls and the app header */
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+  max-width: 340px;
+}
+
+.toast {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 10px;
+  padding: 8px 12px;
+  border-radius: 6px;
+  font-size: 13px;
+  background: rgba(15, 23, 42, 0.95);
+  color: #e2e8f0;
+  border: 1px solid rgba(148, 163, 184, 0.4);
+}
+
+.toast-error {
+  border-color: rgba(239, 68, 68, 0.7);
+  color: #fecaca;
+}
+
+.toast-info {
+  border-color: rgba(148, 163, 184, 0.5);
+}
+
+.toast-close {
+  flex-shrink: 0;
+  font-size: 14px;
+  line-height: 1;
+  padding: 2px 6px;
+  border-radius: 4px;
+  border: none;
+  background: transparent;
+  color: #94a3b8;
+  cursor: pointer;
+}
+
+.toast-close:hover {
+  color: #e2e8f0;
+}
+
+/* ISS-008 — the Time section's notifications opt-in button (same look as .time-controls buttons) */
+.notif-toggle {
+  margin-top: 8px;
+  font-size: 12px;
+  padding: 4px 10px;
+  border-radius: 4px;
+  border: 1px solid rgba(148, 163, 184, 0.4);
+  background: rgba(30, 41, 59, 0.9);
+  color: #e2e8f0;
+  cursor: pointer;
+}
+
+.notif-toggle:disabled {
+  opacity: 0.5;
+  cursor: default;
+}

app/page.tsx

@@ -1,11 +1,14 @@
 'use client';
 
 import dynamic from 'next/dynamic';
-import { useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import LeftPane from '@/components/LeftPane';
 import RightPane from '@/components/RightPane';
+import ToastStack from '@/components/Toasts';
 import type { HoverTarget } from '@/components/hoverTypes';
 import { useGameState } from '@/lib/useGameState';
+import { useToasts } from '@/lib/useToasts';
+import { diffSnapshots } from '@/lib/deriveEvents';
 
 const Map = dynamic(() => import('@/components/Map'), { ssr: false });
 
@@ -19,12 +22,32 @@ export default function Home() {
   // either pane highlights the matching plane/route/airports on the map.
   const [hovered, setHovered] = useState<HoverTarget | null>(null);
 
+  // ISS-008 (v0.17.0): bottom-right toasts — action errors from both panes plus game events
+  // derived by diffing consecutive snapshots (no server event feed exists).
+  const { toasts, push, dismiss } = useToasts();
+  const onError = (message: string) => push('error', message);
+
+  // Diff each new snapshot against the previous one → info toasts. When the window is hidden
+  // and notifications are granted, mirror them as browser notifications too.
+  const prevSnapshotRef = useRef<typeof state>(null);
+  useEffect(() => {
+    if (state === null) return;
+    for (const event of diffSnapshots(prevSnapshotRef.current, state)) {
+      push('info', event.message);
+      if (document.hidden && 'Notification' in window && Notification.permission === 'granted') {
+        new Notification('Flight Ops', { body: event.message });
+      }
+    }
+    prevSnapshotRef.current = state;
+  }, [state, push]);
+
   return (
     <div className="app-shell">
-      <LeftPane state={state} loading={loading} error={error} onRefresh={refresh} onHover={setHovered} />
+      <LeftPane state={state} loading={loading} error={error} onRefresh={refresh} onHover={setHovered} onError={onError} />
       {/* v0.11.0 — the same polled snapshot drives the map's plane markers + route lines */}
       <Map state={state} hovered={hovered} />
-      <RightPane state={state} loading={loading} applySnapshot={applySnapshot} onHover={setHovered} />
+      <RightPane state={state} loading={loading} applySnapshot={applySnapshot} onHover={setHovered} onError={onError} />
+      <ToastStack toasts={toasts} onDismiss={dismiss} />
     </div>
   );
 }