feat(notifications): click a notification to jump to its related page

Every notification surface now deep-links to where the staff member needs to act:
- bell dropdown: clicking an actionable notification navigates and closes the
  dropdown (platform broadcasts still expand inline to show their text)
- notifications page: rows navigate to the right page
- in-app toast: gains a "View" action button
- desktop/Windows popup: clicking it focuses the tab and navigates

Routing is now permission-aware via a single resolver (notification-routes.ts):
a new-order alert sends a kitchen user to /kds, a cashier to /pos, and a floor
user to /tables — never to a page their role can't open; a waiter call → /tables.
This also fixes the old bug where table_call_waiter (which carries a referenceId)
wrongly routed to /kds. Toast/desktop clicks navigate client-side through a small
event bridge mounted in the dashboard shell.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/dashboard/src/lib/notify.ts

@@ -4,12 +4,17 @@ import { ApiClientError } from "@/lib/api/client";
 export type NotifyOptions = {
   description?: string;
   duration?: number;
+  /** Optional click-through button (e.g. "View" → navigate to the related page). */
+  action?: { label: string; onClick: () => void };
 };
 
 function baseOptions(opts?: NotifyOptions) {
   return {
     description: opts?.description,
     duration: opts?.duration ?? 4000,
+    action: opts?.action
+      ? { label: opts.action.label, onClick: opts.action.onClick }
+      : undefined,
   };
 }