Add/csv import options (#420)

* feat(import): add customer and supplier parsing functionality

- Implemented customer file parsing in `lib/import/customers/parser.ts` with support for Excel and CSV formats.
- Created types for detected customer columns and parsed customer rows in `lib/import/customers/types.ts`.
- Added tests for customer classification logic in `lib/import/shared/__tests__/classify.test.ts`.
- Developed classification functions for customers and suppliers in `lib/import/shared/classify.ts`.
- Introduced shared column utility functions in `lib/import/shared/column-utils.ts`.
- Implemented supplier file parsing in `lib/import/suppliers/parser.ts` with validation for various fields.
- Created types for detected supplier columns and parsed supplier rows in `lib/import/suppliers/types.ts`.
- Added tests for supplier column detection and parsing in `lib/import/suppliers/__tests__/column-detector.test.ts` and `lib/import/suppliers/__tests__/parser.test.ts`.

* fix(labels): update 'Svenskt företag' to 'Svenskt företag eller organisation' for clarity

* feat(import): refactor encoding handling for Swedish files and add tests for character preservation

* feat(recapt): implement clearRecaptIdentity function and integrate into logout flow

* feat(bookkeeping): implement copy functionality and next voucher sequence retrieval

* feat(import): enhance customer and supplier import functionality with normalization and event handling

lib/api/schemas.ts

@@ -607,6 +607,60 @@ export const OpeningBalanceExecuteSchema = z.object({
   })).min(2, 'At least two lines are required for double-entry'),
 })
 
+// ============================================================
+// Register import schemas (customers, suppliers)
+// ============================================================
+
+const ImportedCustomerRowSchema = z.object({
+  row_index: z.number().int(),
+  name: z.string().min(1),
+  customer_type: CustomerTypeSchema,
+  org_number: z.string().nullable(),
+  email: z.string().nullable(),
+  phone: z.string().nullable(),
+  address_line1: z.string().nullable(),
+  address_line2: z.string().nullable(),
+  postal_code: z.string().nullable(),
+  city: z.string().nullable(),
+  country: z.string(),
+  vat_number: z.string().nullable(),
+  default_payment_terms: z.number().int().min(0).max(365),
+  notes: z.string().nullable(),
+})
+
+export const CustomerImportExecuteSchema = z.object({
+  rows: z.array(ImportedCustomerRowSchema).min(1, 'At least one row is required'),
+  update_duplicates: z.boolean(),
+})
+
+const ImportedSupplierRowSchema = z.object({
+  row_index: z.number().int(),
+  name: z.string().min(1),
+  supplier_type: SupplierTypeSchema,
+  org_number: z.string().nullable(),
+  email: z.string().nullable(),
+  phone: z.string().nullable(),
+  address_line1: z.string().nullable(),
+  address_line2: z.string().nullable(),
+  postal_code: z.string().nullable(),
+  city: z.string().nullable(),
+  country: z.string(),
+  vat_number: z.string().nullable(),
+  bankgiro: z.string().nullable(),
+  plusgiro: z.string().nullable(),
+  bank_account: z.string().nullable(),
+  iban: z.string().nullable(),
+  bic: z.string().nullable(),
+  default_payment_terms: z.number().int().min(0).max(365),
+  default_currency: z.string(),
+  notes: z.string().nullable(),
+})
+
+export const SupplierImportExecuteSchema = z.object({
+  rows: z.array(ImportedSupplierRowSchema).min(1, 'At least one row is required'),
+  update_duplicates: z.boolean(),
+})
+
 // ============================================================
 // Salary schemas
 // ============================================================