feat(frontend): Add comprehensive bank account management system.

- Add drawer-based bank account connection flow with country/bank selection
- Create bank connection success page with redirect handling
- Add bank connections status card showing all requisitions and their states
- Move account management actions to appropriate sections (add to connections, edit in accounts)
- Implement proper delete functionality for bank connections via GoCardless API
- Add proper TypeScript types for all bank-related data structures
- Improve error handling for bank connection operations with specific HTTP status codes
- Remove transaction data when disconnecting accounts while preserving history

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/routes/bank-connected.tsx

@@ -0,0 +1,57 @@
+import { createFileRoute, useSearch } from "@tanstack/react-router";
+import { CheckCircle, ArrowLeft } from "lucide-react";
+import { Button } from "../components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardHeader,
+  CardTitle,
+} from "../components/ui/card";
+
+function BankConnected() {
+  const search = useSearch({ from: "/bank-connected" });
+
+  return (
+    <div className="min-h-screen flex items-center justify-center bg-background p-4">
+      <Card className="w-full max-w-md">
+        <CardHeader className="text-center pb-2">
+          <div className="mx-auto mb-4">
+            <CheckCircle className="h-16 w-16 text-green-500" />
+          </div>
+          <CardTitle className="text-2xl">Account Connected!</CardTitle>
+        </CardHeader>
+        <CardContent className="text-center space-y-4">
+          <p className="text-muted-foreground">
+            Your bank account has been successfully connected to Leggen. We'll
+            start syncing your transactions shortly.
+          </p>
+
+          {search?.bank && (
+            <p className="text-sm text-muted-foreground">
+              Connected to: <strong>{search.bank}</strong>
+            </p>
+          )}
+
+          <div className="pt-4">
+            <Button
+              onClick={() => (window.location.href = "/settings")}
+              className="w-full"
+            >
+              <ArrowLeft className="h-4 w-4 mr-2" />
+              Go to Settings
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  );
+}
+
+export const Route = createFileRoute("/bank-connected")({
+  component: BankConnected,
+  validateSearch: (search: Record<string, unknown>) => {
+    return {
+      bank: (search.bank as string) || undefined,
+    };
+  },
+});