Add professor share & financial reports UI, expense management page

Adds payout configuration fields (percentage/hourly + per-session
expense allowance) with a live payout preview to the class form,
a new Financial Reports page (per-class and date-range/monthly tabs,
per-session drill-down dialog) with reusable stat cards, and an
Institutional Expenses management page. Registers routes, sidebar
navigation, and permission constants for the new financial_reports
and expenses permissions.

src/components/layout/AppSidebar.vue

@@ -60,6 +60,8 @@ const menuGroups = computed(() => {
       label: 'مالی و ارتباطات',
       items: [
         { label: 'امور مالی و پرداخت‌ها', icon: 'pi pi-wallet', to: '/payments' },
+        { label: 'گزارش‌های مالی', icon: 'pi pi-chart-line', to: '/financial-reports', permission: PERMISSIONS.FINANCIAL_REPORTS_READ },
+        { label: 'هزینه‌های موسسه', icon: 'pi pi-money-bill', to: '/expenses', permission: PERMISSIONS.EXPENSES_READ },
         { label: 'اطلاعیه‌ها', icon: 'pi pi-bell', to: '/notifications' },
         { label: 'درخواست‌های تماس', icon: 'pi pi-comments', to: '/contact-inquiries' },
         { label: 'ثبت‌نام‌های در انتظار', icon: 'pi pi-user-plus', to: '/pending-students', permission: PERMISSIONS.PENDING_STUDENTS_READ }