Full site redesign, help system, and dashboard stats fixes

Multi-phase visual facelift (design tokens, dashboards, sidebar/navbar
shell, per-page help guides, and a layout/content pass across every
remaining page) plus backend fixes to the dashboard KPI stats:

- Admin/Supervisor dashboard KPIs (revenue, donations, registrations,
  tickets sold) now use a rolling trailing-month window (today back one
  calendar month, e.g. 9 May - 8 June if today is 8 June) instead of
  calendar month-to-date, which under-counted for most of the month.
  The comparison window shifts the same way, so like is still compared
  with like.
- Reports deep-links from those stat tiles now match the same window
  (range=trailing_month, replacing range=this_month).
- Design tokens (brand-* Tailwind scale + shadcn CSS variables), a
  site-wide contextual help button, fixed dashboard sidebar/navbar,
  Admin/Supervisor/Staff/User dashboard rebuilds backed by a new
  GET /api/stats/overview endpoint, a dedicated Contact page, Site
  Settings restyle with WhatsApp config folded in, and an Account
  activity feed backed by a new SecurityEvent model.
- Every remaining page (home, events, registration flow, auth, legal,
  payment results, and every Admin/Supervisor/Staff/User tool page)
  restyled onto the same design tokens, several with real layout
  upgrades (home hero, events list/detail, donate page, auth pages).
- 20+ new dedicated help guides so the whole site has page-specific
  help content instead of falling back to a generic guide.
- Assorted fixes surfaced along the way: donation-leg double-counting
  in payment stats, donations not counting toward revenue, refund
  netting in per-method report breakdowns, and donation
  over-allocation after a refund.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/app/dashboard/supervisor/event-options/page.tsx

@@ -5,6 +5,7 @@ import { useAuth } from "@/hooks/useAuth";
 import { useRouter, useSearchParams } from "next/navigation";
 import { apiFetch } from "@/lib/api";
 import { useDismissingState } from "@/hooks/useDismissingState";
+import { Ticket } from "lucide-react";
 
 // Format a Date (or date-like input) to the value expected by <input type="datetime-local">
 // This returns local time (browser timezone) as YYYY-MM-DDTHH:mm
@@ -85,8 +86,8 @@ function EarlyBirdTiersEditor({ option, onSave }: { option: any; onSave: (tiers:
             </ul>
           )}
           <div className="flex items-center gap-2">
-            <button type="button" className="text-xs px-2 py-1 rounded bg-indigo-600 text-white hover:bg-indigo-700" onClick={addRow}>Add tier</button>
-            <button type="button" className="text-xs px-2 py-1 rounded bg-blue-600 text-white hover:bg-blue-700 disabled:opacity-60" onClick={save} disabled={saving}>{saving ? 'Saving…' : 'Save tiers'}</button>
+            <button type="button" className="text-xs px-2 py-1 rounded bg-brand-600 text-white hover:bg-brand-700" onClick={addRow}>Add tier</button>
+            <button type="button" className="text-xs px-2 py-1 rounded bg-brand-600 text-white hover:bg-brand-700 disabled:opacity-60" onClick={save} disabled={saving}>{saving ? 'Saving…' : 'Save tiers'}</button>
           </div>
         </div>
       )}
@@ -202,9 +203,14 @@ function EventOptionsContent() {
 
   return (
     <div className="max-w-5xl mx-auto w-full p-6">
-      <div className="flex items-center justify-between mb-4">
-        <h1 className="text-2xl font-semibold">Event options</h1>
-        <button className="px-3 py-1.5 text-sm rounded bg-gray-100 hover:bg-gray-200 text-gray-800 shadow-sm" onClick={() => router.push('/dashboard/supervisor/events')}>Back</button>
+      <div className="flex items-center justify-between mb-4 flex-wrap gap-3">
+        <div className="flex items-center gap-3">
+          <div className="w-10 h-10 rounded-xl bg-brand-50 flex items-center justify-center shrink-0">
+            <Ticket className="w-5 h-5 text-brand-600" />
+          </div>
+          <h1 className="text-2xl font-semibold text-gray-900">Event options</h1>
+        </div>
+        <button className="px-3 py-1.5 text-sm rounded-lg bg-gray-100 hover:bg-gray-200 text-gray-800 shadow-sm" onClick={() => router.push('/dashboard/supervisor/events')}>Back</button>
       </div>
 
       {!canView && (
@@ -280,7 +286,7 @@ function EventOptionsContent() {
               <input className="border rounded px-3 py-2 text-sm" placeholder="Name" value={newOpt.name} onChange={e => setNewOpt({ ...newOpt, name: e.target.value })} />
               <input className="border rounded px-3 py-2 text-sm" placeholder="Price" type="number" step="0.01" value={newOpt.price} onChange={e => setNewOpt({ ...newOpt, price: e.target.value })} />
               <label className="text-sm flex items-center gap-2"><input type="checkbox" checked={newOpt.isMainTicket} onChange={e => setNewOpt({ ...newOpt, isMainTicket: e.target.checked })} /> Main ticket</label>
-              <button onClick={createOption} className="px-3 py-1.5 text-sm rounded bg-indigo-600 text-white hover:bg-indigo-700 shadow-sm">Create option</button>
+              <button onClick={createOption} className="px-3 py-1.5 text-sm rounded bg-brand-600 text-white hover:bg-brand-700 shadow-sm">Create option</button>
             </div>
           </div>
         </div>