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/components/reports/ReportsShell.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import React, { useMemo, useState } from "react";
-import { ArrowLeft, HelpCircle, Search } from "lucide-react";
+import { ArrowLeft, Search } from "lucide-react";
 import { REPORTS, REPORT_CATEGORIES, type ReportKey, type ReportCategory } from "./ReportCatalog";
 import EventsDropdown from "./EventsDropdown";
 
@@ -17,7 +17,6 @@ export default function ReportsShell({
   dateFrom, setDateFrom, dateTo, setDateTo,
   report, setReport,
   onViewReport, busy,
-  onOpenGuide,
   onBack,
 }: {
   events: EventLite[]; isAdmin: boolean;
@@ -28,7 +27,6 @@ export default function ReportsShell({
   dateFrom: string; setDateFrom: (v: string) => void; dateTo: string; setDateTo: (v: string) => void;
   report: ReportKey; setReport: (r: ReportKey) => void;
   onViewReport: () => void; busy: boolean;
-  onOpenGuide: () => void;
   onBack?: () => void;
 }) {
   const [search, setSearch] = useState("");
@@ -141,14 +139,6 @@ export default function ReportsShell({
             )}
           </div>
         </div>
-
-        <button type="button" className="w-full flex items-start gap-3 text-left text-sm border rounded-xl p-4 bg-white shadow-sm hover:bg-gray-50" onClick={onOpenGuide}>
-          <HelpCircle className="w-5 h-5 text-gray-500 shrink-0" />
-          <span>
-            <span className="block font-medium text-gray-800">Need help?</span>
-            <span className="block text-xs text-gray-500">View our reporting guide</span>
-          </span>
-        </button>
       </aside>
 
       {/* Main: categories, report grid */}
@@ -158,7 +148,7 @@ export default function ReportsShell({
             <button
               key={c}
               type="button"
-              className={"px-3 py-1.5 text-sm rounded-lg border " + (category === c ? "bg-indigo-600 text-white border-indigo-600" : "bg-white text-gray-700 border-gray-200 hover:bg-gray-50")}
+              className={"px-3 py-1.5 text-sm rounded-lg border " + (category === c ? "bg-brand-600 text-white border-brand-600" : "bg-white text-gray-700 border-gray-200 hover:bg-gray-50")}
               onClick={() => setCategory(c)}
             >
               {c}
@@ -175,7 +165,7 @@ export default function ReportsShell({
                 key={r.key}
                 type="button"
                 onClick={() => setReport(r.key)}
-                className={"text-left border rounded-xl p-4 transition " + (selected ? "border-indigo-500 ring-2 ring-indigo-100 bg-indigo-50/40" : "border-gray-200 hover:border-gray-300 bg-white")}
+                className={"text-left border rounded-xl p-4 transition " + (selected ? "border-brand-500 ring-2 ring-brand-100 bg-brand-50/40" : "border-gray-200 hover:border-gray-300 bg-white")}
               >
                 <div className="w-9 h-9 rounded-lg bg-gray-100 flex items-center justify-center mb-3">
                   <Icon className="w-5 h-5 text-gray-600" />
@@ -199,7 +189,7 @@ export default function ReportsShell({
           <button
             disabled={busy}
             onClick={onViewReport}
-            className="px-4 py-2 text-sm rounded-lg bg-indigo-600 text-white hover:bg-indigo-700 disabled:opacity-50"
+            className="px-4 py-2 text-sm rounded-lg bg-brand-600 text-white hover:bg-brand-700 disabled:opacity-50"
           >
             {busy ? "Loading…" : "View report"}
           </button>