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/types/api.ts

@@ -242,3 +242,38 @@ export interface SyncOperationsResponse {
   operations: SyncOperation[];
   count: number;
 }
+
+// Bank-related types
+export interface BankInstitution {
+  id: string;
+  name: string;
+  bic?: string;
+  transaction_total_days: number;
+  countries: string[];
+  logo?: string;
+}
+
+export interface BankRequisition {
+  id: string;
+  institution_id: string;
+  status: string;
+  status_display?: string;
+  created: string;
+  link: string;
+  accounts: string[];
+}
+
+export interface BankConnectionStatus {
+  bank_id: string;
+  bank_name: string;
+  status: string;
+  status_display: string;
+  created_at: string;
+  requisition_id: string;
+  accounts_count: number;
+}
+
+export interface Country {
+  code: string;
+  name: string;
+}