feat: Accounting web module — COA, journals, expenses, accounts, reports + nav (FIBEROPS-234-239)

- Chart of Accounts (FIBEROPS-234): type-filtered table, add/seed/toggle-active
- Journal Entries (FIBEROPS-235): double-entry form with debit=credit validation, read-only view modal
- Expenses (FIBEROPS-236): date-range filtered table, record expense against expense accounts
- Company Accounts + Transfers (FIBEROPS-237): balance cards, add account modal, transfer modal, transfers table
- Financial Reports (FIBEROPS-238): Trial Balance, P&L, Balance Sheet, Cash Flow with date pickers
- Sidebar nav entry (FIBEROPS-239): Accounting link with BookOpen icon, placed between Reports and Settings
- AccountingNav horizontal sub-nav component shared across all accounting pages
- New types: Account, JournalEntry, Expense, CompanyAccount, Transfer and report types added to src/types/index.ts

src/components/layout/Sidebar.tsx

@@ -17,6 +17,7 @@ import {
   Wifi,
   Briefcase,
   BarChart2,
+  BookOpen,
   X,
 } from "lucide-react";
 
@@ -32,6 +33,7 @@ const navItems = [
   { href: "/users", label: "Users", icon: UserCog },
   { href: "/audit-log", label: "Audit Log", icon: ClipboardList },
   { href: "/reports", label: "Reports", icon: BarChart2 },
+  { href: "/accounting", label: "Accounting", icon: BookOpen },
   { href: "/settings", label: "Settings", icon: Settings },
 ];