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/hooks/useHelpGuide.ts

@@ -0,0 +1,42 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+/**
+ * Open/close state for a help guide, with per-page "don't show again"
+ * persistence. `storageKey` should be a stable slug identifying the guide's
+ * content (e.g. "reports", "dashboard-user", "general") — each slug gets an
+ * independent dismissal flag, so dismissing one page's guide doesn't
+ * suppress another's.
+ */
+export function useHelpGuide(storageKey: string) {
+  const [open, setOpen] = useState(false);
+  const dismissedKey = `hope_events_help_dismissed_${storageKey}`;
+
+  // Show automatically on first visit to this guide, unless dismissed for good.
+  useEffect(() => {
+    try {
+      if (typeof window !== "undefined" && window.localStorage.getItem(dismissedKey) !== "1") {
+        setOpen(true);
+      }
+    } catch {
+      // localStorage unavailable (private browsing, etc.) — just don't auto-show.
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [dismissedKey]);
+
+  const openGuide = () => setOpen(true);
+
+  const closeGuide = (dontShowAgain: boolean) => {
+    setOpen(false);
+    if (dontShowAgain) {
+      try {
+        window.localStorage.setItem(dismissedKey, "1");
+      } catch {
+        // ignore
+      }
+    }
+  };
+
+  return { open, openGuide, closeGuide };
+}