Fix/vat parent accounts (#438)

* feat(enable-banking): add support for account selection and syncing

- Updated StoredAccount interface to include an 'enabled' flag for account syncing preferences.
- Enhanced ensureFiscalPeriod function to handle overlapping fiscal periods with posted entries and opening balances.
- Added tests for fiscal period validation and account syncing logic.
- Implemented AccountPickerDialog component for user account selection.
- Created API routes for PATCH /accounts and POST /sync to manage account syncing.
- Introduced 'pending_selection' status for bank connections to allow user account selection before syncing.
- Updated database migration to support new connection status and backfill existing accounts with enabled=true.

* feat(enable-banking): implement account selection and consent event logging

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Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

types/index.ts

@@ -151,7 +151,9 @@ export interface ProcessingHistoryEvent {
 }
 
 // Bank connection status
-export type BankConnectionStatus = 'pending' | 'active' | 'expired' | 'revoked' | 'error'
+// 'pending_selection' = PSD2 consent granted, awaiting user to pick which
+// accounts to actually sync. No transactions are pulled in this state.
+export type BankConnectionStatus = 'pending' | 'pending_selection' | 'active' | 'expired' | 'revoked' | 'error'
 
 // Currency types
 export type Currency = 'SEK' | 'EUR' | 'USD' | 'GBP' | 'NOK' | 'DKK'