Add Calendar dialog, Prescriptions & Messages pages, note delete confirm

- Appointments: a Calendar button next to Add opens a month-grid dialog
  (reuses the Calendar primitive + shared ScheduleList); the schedule day is
  marked and selecting it lists that day's appointments.
- Patients sub-nav: new Prescriptions page (mock list + KPIs) with a compact
  "New prescription" dialog reusing the patient quick-search pattern.
- Notes: deleting a note now goes through a reusable ConfirmDialog instead of
  deleting immediately.
- New top-level Messages page: two-pane email-style inbox (list + reading pane
  with mock reply composer), mirroring the Notes layout.
- Sidebar logo bumped from size-9 to size-10.

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

frontend/app/(app)/messages/page.tsx

@@ -0,0 +1,10 @@
+import { MessagesView } from "@/components/messages/messages-view";
+import { SidebarInset } from "@/components/ui/sidebar";
+
+export default function MessagesPage() {
+  return (
+    <SidebarInset className="flex flex-1 flex-col overflow-hidden">
+      <MessagesView />
+    </SidebarInset>
+  );
+}

frontend/app/(app)/prescriptions/page.tsx

@@ -0,0 +1,10 @@
+import { PrescriptionsView } from "@/components/prescriptions/prescriptions-view";
+import { SidebarInset } from "@/components/ui/sidebar";
+
+export default function PrescriptionsPage() {
+  return (
+    <SidebarInset className="flex flex-1 flex-col overflow-y-auto">
+      <PrescriptionsView />
+    </SidebarInset>
+  );
+}