feat(web): command palette, toasts, and global shell chrome

- CommandPalette (Alt+K): fuzzy action launcher with keyboard nav.
- Toasts: ephemeral notification stack + provider.
- useGlobalHotkeys: Alt+K palette toggle, G-chord navigation
  (G D/F/M/L/B/A/S/U/E/C), respects editable-element focus.
- Layout/App: wire ToastProvider at root, mount the palette inside the
  authed shell, introduce the global search box in the top bar.
- MazeNETRoute now renders TopologyList inline when no ?topology is
  present, instead of bouncing through a redirect.
- index.css: a few global token tweaks consumed by the new chrome.

Fixes a latent breakage: Config.tsx and MazeNET already imported
./Toasts/useToast but the directory was never committed.

decnet_web/src/components/Toasts/ToastProvider.tsx

@@ -0,0 +1,33 @@
+import React, { useCallback, useEffect, useRef, useState } from 'react';
+import Toasts from './Toasts';
+import { ToastContext } from './toast-context';
+import type { Toast, ToastInput } from './toast-context';
+
+const DISMISS_MS = 3200;
+
+export const ToastProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const [items, setItems] = useState<Toast[]>([]);
+  const timers = useRef<Map<number, ReturnType<typeof setTimeout>>>(new Map());
+
+  const push = useCallback((t: ToastInput) => {
+    const id = Date.now() + Math.random();
+    setItems(prev => [...prev, { ...t, id }]);
+    const timer = setTimeout(() => {
+      setItems(prev => prev.filter(x => x.id !== id));
+      timers.current.delete(id);
+    }, DISMISS_MS);
+    timers.current.set(id, timer);
+  }, []);
+
+  useEffect(() => {
+    const map = timers.current;
+    return () => { map.forEach(clearTimeout); map.clear(); };
+  }, []);
+
+  return (
+    <ToastContext.Provider value={{ push }}>
+      {children}
+      <Toasts items={items} />
+    </ToastContext.Provider>
+  );
+};

decnet_web/src/components/Toasts/Toasts.css

@@ -0,0 +1,33 @@
+.toast-stack {
+  position: fixed;
+  bottom: 24px;
+  left: 24px;
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+  z-index: 70;
+  pointer-events: none;
+}
+
+.toast {
+  background: var(--panel);
+  border: 1px solid var(--matrix);
+  padding: 10px 14px;
+  font-size: 0.72rem;
+  letter-spacing: 1px;
+  min-width: 260px;
+  display: flex;
+  gap: 10px;
+  align-items: center;
+  color: var(--matrix);
+  animation: toast-in 0.25s var(--ease);
+}
+
+.toast.matrix { border-color: var(--matrix); color: var(--matrix); }
+.toast.violet { border-color: var(--violet); color: var(--violet); }
+.toast.alert  { border-color: var(--alert);  color: var(--alert); }
+
+@keyframes toast-in {
+  from { transform: translateX(-20px); opacity: 0; }
+  to   { transform: none;               opacity: 1; }
+}

decnet_web/src/components/Toasts/Toasts.tsx

@@ -0,0 +1,44 @@
+import React from 'react';
+import {
+  CheckCircle, RefreshCw, Download, Upload, Pause, Play, AlertTriangle,
+  Info, Terminal, Activity, ShieldAlert,
+} from 'lucide-react';
+import type { Toast } from './toast-context';
+import './Toasts.css';
+
+const ICON_MAP: Record<string, React.ComponentType<{ size?: number }>> = {
+  'check-circle': CheckCircle,
+  'refresh-cw': RefreshCw,
+  'download': Download,
+  'upload': Upload,
+  'pause': Pause,
+  'play': Play,
+  'alert-triangle': AlertTriangle,
+  'info': Info,
+  'terminal': Terminal,
+  'activity': Activity,
+  'shield-alert': ShieldAlert,
+};
+
+interface Props {
+  items: Toast[];
+}
+
+const Toasts: React.FC<Props> = ({ items }) => {
+  if (items.length === 0) return null;
+  return (
+    <div className="toast-stack">
+      {items.map(t => {
+        const Icon = ICON_MAP[t.icon ?? 'check-circle'] ?? CheckCircle;
+        return (
+          <div key={t.id} className={`toast ${t.tone ?? ''}`.trim()}>
+            <Icon size={14} />
+            <span>{t.text}</span>
+          </div>
+        );
+      })}
+    </div>
+  );
+};
+
+export default Toasts;

decnet_web/src/components/Toasts/toast-context.ts

@@ -0,0 +1,19 @@
+import { createContext } from 'react';
+
+export type ToastTone = 'matrix' | 'violet' | 'alert';
+
+export interface ToastInput {
+  text: string;
+  icon?: string;
+  tone?: ToastTone;
+}
+
+export interface Toast extends ToastInput {
+  id: number;
+}
+
+export interface ToastContextValue {
+  push: (t: ToastInput) => void;
+}
+
+export const ToastContext = createContext<ToastContextValue | null>(null);

decnet_web/src/components/Toasts/useToast.ts

@@ -0,0 +1,9 @@
+import { useContext } from 'react';
+import { ToastContext } from './toast-context';
+import type { ToastContextValue } from './toast-context';
+
+export function useToast(): ToastContextValue {
+  const ctx = useContext(ToastContext);
+  if (!ctx) throw new Error('useToast must be used inside <ToastProvider>');
+  return ctx;
+}