Refactor bookkeeping error handling and introduce new error classes (#356)

- Introduced new error classes for better error categorization:
  - JournalEntryNotBalancedError
  - FiscalPeriodNotFoundError
  - EntryDateOutsideFiscalPeriodError
  - JournalEntryNotFoundError
  - CannotReverseNonPostedError
  - CannotCorrectNonPostedError
  - EntryAlreadyReversedError
  - CurrencyRevaluationAlreadyExistsError
  - InvalidMappingResultError
  - BookkeepingDatabaseError

- Updated existing functions in engine.ts and transaction-entries.ts to throw specific errors instead of generic ones.
- Enhanced error response handling in get-error-message.ts to provide localized messages for new error types.
- Added unit tests for new error classes and error handling functions to ensure correctness and coverage.

components/bookkeeping/CorrectionEntryDialog.tsx

@@ -15,6 +15,7 @@ import { Badge } from '@/components/ui/badge'
 import { AccountNumber } from '@/components/ui/account-number'
 import AccountCombobox from '@/components/bookkeeping/AccountCombobox'
 import { useToast } from '@/components/ui/use-toast'
+import { getErrorMessage } from '@/lib/errors/get-error-message'
 import { Plus, Trash2 } from 'lucide-react'
 import type { JournalEntry, JournalEntryLine, BASAccount } from '@/types'
 
@@ -109,7 +110,10 @@ export default function CorrectionEntryDialog({ entry, open, onOpenChange, onCor
       const result = await res.json()
 
       if (!res.ok) {
-        throw new Error(result.error || 'Failed to create correction')
+        const error = new Error('Failed to create correction') as Error & { body?: unknown; status?: number }
+        error.body = result
+        error.status = res.status
+        throw error
       }
 
       const correctedId = result.data?.corrected?.id
@@ -126,9 +130,10 @@ export default function CorrectionEntryDialog({ entry, open, onOpenChange, onCor
       onOpenChange(false)
       onCorrected()
     } catch (err) {
+      const anyErr = err as { body?: unknown; status?: number }
       toast({
         title: 'Fel',
-        description: err instanceof Error ? err.message : 'Kunde inte skapa ändringsverifikation',
+        description: getErrorMessage(anyErr.body ?? err, { context: 'journal_entry', statusCode: anyErr.status }),
         variant: 'destructive',
       })
     } finally {

components/invoices/PaymentBookingDialog.tsx

@@ -16,6 +16,7 @@ import { Badge } from '@/components/ui/badge'
 import { useToast } from '@/components/ui/use-toast'
 import AccountCombobox from '@/components/bookkeeping/AccountCombobox'
 import { proposePaymentLines } from '@/lib/bookkeeping/propose-payment-lines'
+import { getErrorMessage } from '@/lib/errors/get-error-message'
 import { formatCurrency } from '@/lib/utils'
 import { createClient } from '@/lib/supabase/client'
 import { useCompany } from '@/contexts/CompanyContext'
@@ -187,15 +188,19 @@ export default function PaymentBookingDialog({
 
       if (!response.ok) {
         const data = await response.json()
-        throw new Error(data.error || 'Kunde inte markera som betald')
+        const error = new Error('Kunde inte markera som betald') as Error & { body?: unknown; status?: number }
+        error.body = data
+        error.status = response.status
+        throw error
       }
 
       onOpenChange(false)
       onSuccess()
     } catch (error) {
+      const anyErr = error as { body?: unknown; status?: number }
       toast({
         title: 'Bokföring misslyckades',
-        description: error instanceof Error ? error.message : 'Försök igen.',
+        description: getErrorMessage(anyErr.body ?? error, { context: 'invoice', statusCode: anyErr.status }),
         variant: 'destructive',
       })
     }