feat: Comprehensive contextual headers for all pages

Applied "bigger picture" thinking - added contextual headers to ALL submenu pages consistently.

Problem: Only some pages had headers, creating inconsistent UX

Issues Fixed:

1. Dashboard Submenu Pages - All Now Have Headers
   Before: Only Overview had header
   After: All 6 pages have headers (Revenue, Orders, Products, Customers, Coupons, Taxes)

2. Settings Pages Desktop - Show Headers (Except Payments)
   Before: PageHeader was md:hidden on all pages
   After: Shows on desktop for Settings pages, hidden only for Payments (special case)

Implementation:
- Added usePageHeader to 6 Dashboard submenu pages
- Modified PageHeader to show on desktop by default
- Auto-detect Payments page and hide header there

Result:
- ALL Dashboard pages have contextual headers
- ALL Settings pages have contextual headers on desktop
- Payments page special case handled
- Consistent UX across entire app
- No more bald pages!

Files Modified: 6 Dashboard pages + PageHeader.tsx

admin-spa/src/routes/Dashboard/Customers.tsx

@@ -1,4 +1,4 @@
-import React, { useState, useMemo } from 'react';
+import React, { useState, useMemo, useEffect } from 'react';
 import { BarChart, Bar, LineChart, Line, XAxis, YAxis, CartesianGrid, Tooltip, ResponsiveContainer, Legend } from 'recharts';
 import { Users, TrendingUp, DollarSign, ShoppingCart, UserPlus, UserCheck, Info } from 'lucide-react';
 import { __ } from '@/lib/i18n';
@@ -12,11 +12,18 @@ import { ChartCard } from './components/ChartCard';
 import { DataTable, Column } from './components/DataTable';
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
 import { DUMMY_CUSTOMERS_DATA, CustomersData, TopCustomer } from './data/dummyCustomers';
+import { usePageHeader } from '@/contexts/PageHeaderContext';
 
 export default function CustomersAnalytics() {
+  const { setPageHeader, clearPageHeader } = usePageHeader();
   const { period } = useDashboardPeriod();
   const store = getStoreCurrency();
 
+  useEffect(() => {
+    setPageHeader(__('Customers'));
+    return () => clearPageHeader();
+  }, [setPageHeader, clearPageHeader]);
+
   // Fetch real data or use dummy data based on toggle
   const { data, isLoading, error, refetch } = useCustomersAnalytics(DUMMY_CUSTOMERS_DATA);