Add invoice dialog and enhance Cashflow, Clients, Invoices, and Net Worth pages

- Introduced AddInvoiceDialog component for creating new invoices with client selection and form validation.
- Updated CashflowPage to include dialogs for adding income, expenses, and transactions, improving user interaction.
- Enhanced ClientsPage with a dialog for adding new clients, streamlining client management.
- Improved InvoicesPage with a dialog for creating new invoices, facilitating better invoice management.
- Updated NetWorthPage to include dialogs for adding assets and liabilities, enhancing financial tracking capabilities.

frontend-web/src/pages/ClientsPage.tsx

@@ -1,8 +1,11 @@
+import {useState} from 'react';
 import {Card, CardContent} from '@/components/ui/card';
 import {Button} from '@/components/ui/button';
 import {useAppSelector} from '@/store';
+import AddClientDialog from '@/components/dialogs/AddClientDialog';
 
 export default function ClientsPage() {
+  const [dialogOpen, setDialogOpen] = useState(false);
   const {clients, invoices} = useAppSelector(state => state.invoices);
 
   const getClientStats = (clientId: string) => {
@@ -29,7 +32,7 @@ export default function ClientsPage() {
             <div><span className="text-muted-foreground">Outstanding</span> <span className="font-medium">{fmt(totalOutstanding)}</span></div>
           </div>
         </div>
-        <Button size="sm">Add Client</Button>
+        <Button size="sm" onClick={() => setDialogOpen(true)}>Add Client</Button>
       </div>
 
       {/* Clients Grid */}
@@ -64,12 +67,14 @@ export default function ClientsPage() {
         })}
         
         {/* Add client card */}
-        <Card className="card-elevated border-dashed cursor-pointer hover:bg-accent/50 transition-colors">
+        <Card className="card-elevated border-dashed cursor-pointer hover:bg-accent/50 transition-colors" onClick={() => setDialogOpen(true)}>
           <CardContent className="p-4 flex items-center justify-center h-full min-h-[100px]">
             <span className="text-sm text-muted-foreground">+ Add Client</span>
           </CardContent>
         </Card>
       </div>
+
+      <AddClientDialog open={dialogOpen} onOpenChange={setDialogOpen} />
     </div>
   );
 }