feat: per-line VAT, invoice document types, ledger-based VAT declaration, bank reconciliation, and pagination

Per-line VAT rates:
- Add generatePerRateLines() to group invoice items by vat_rate with separate
  revenue + VAT lines per rate group (invoice-entries.ts)
- Add getAvailableVatRates() and getVatTreatmentForRate() (vat-rules.ts)
- PDF template shows per-line VAT column and per-rate totals for mixed-rate invoices
- Invoice create/review UI supports per-line rate selection
- Types: add vat_rate/vat_amount to InvoiceItem, vat_rate to CreateInvoiceItemInput

Invoice document types (proforma, delivery note):
- Add InvoiceDocumentType, document_type and converted_from_id to Invoice type
- PDF hides prices for delivery notes, adds proforma notice
- Email templates support all document types
- mark-paid skips journal entries for non-invoice document types
- Migration 031: invoice_document_type

Accounting method support:
- Add AccountingMethod type (accrual/cash)
- Migration 032: add_accounting_method column to company_settings

VAT declaration rewrite:
- Rewrite to read directly from general ledger (26xx/3xxx account lines)
  instead of aggregating invoices/transactions/receipts
- ACCOUNT_RUTA mapping drives momsdeklaration boxes from GL balances

Bank reconciliation:
- Transaction ingest now pre-fetches unlinked GL lines and attempts
  auto-reconciliation during import
- Add transaction.reconciled event type
- Add ReconciliationMethod type and reconciliation_method on Transaction
- Migration 030: bank_reconciliation
- New reconciliation engine, API routes, and BankReconciliationView component

Pagination (fetchAllRows):
- New lib/supabase/fetch-all.ts overcomes PostgREST 1000-row limit
- Adopted in all report generators, SIE/SRU export, account list APIs

Fiscal period validation:
- New validate-period-duration.ts enforces max 18 months per BFL 3 kap.
- Applied in period-service.ts and fiscal-periods API

Account mapper simplification:
- Remove Levenshtein/fuzzy matching, use exact account number match only

Swedbank parser improvements:
- Support abbreviated headers (Clnr, Bokfdag, Radnr)
- Use Referens column as counterparty

Chart of accounts management:
- Add DELETE endpoint with system account and usage protection
- PUT uses partial updates
- New AccountCombobox, AddAccountDialog, EditAccountDialog, ChartOfAccountsManager

Tax deadline corrections:
- Rewrite inkomstdeklaration_ab using Skatteverket lookup table
- Rewrite arsredovisning deadline to 7 months after FY end per ÅRL 8:3

Onboarding first fiscal year:
- Add first fiscal year toggle with date pickers and 18-month validation

UI terminology:
- Change "okategoriserad/kategorisera" to "obokförd/bokföra" throughout

Report column fix:
- Fix start_date/end_date to period_start/period_end in report queries

Supplier invoice input:
- CreateSupplierInvoiceItemInput uses amount field (legacy quantity/unit_price kept)

Misc:
- SIE import uses upsert for idempotent account creation
- account-descriptions.ts falls back to BAS reference data
- Add invoice_default_notes to CompanySettings
- Update CLAUDE.md to reflect current project state

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/api/transactions/[id]/match-invoice/route.ts

@@ -1,58 +1,15 @@
 import { createClient } from '@/lib/supabase/server'
 import { NextResponse } from 'next/server'
-import { createJournalEntry, findFiscalPeriod } from '@/lib/bookkeeping/engine'
 import {
-  getRevenueAccount,
-  getOutputVatAccount,
+  createInvoicePaymentJournalEntry,
+  createInvoiceCashEntry,
 } from '@/lib/bookkeeping/invoice-entries'
-import type { Transaction, Invoice, CreateJournalEntryInput, EntityType, VatTreatment } from '@/types'
+import type { EntityType, Invoice } from '@/types'
 
 interface MatchInvoiceRequest {
   invoice_id: string
 }
 
-/**
- * Ensure a fiscal period exists for the given date, create one if needed
- */
-async function ensureFiscalPeriod(
-  supabase: Awaited<ReturnType<typeof createClient>>,
-  userId: string,
-  date: string
-): Promise<string | null> {
-  // Check if a fiscal period already covers this date
-  const existingPeriodId = await findFiscalPeriod(userId, date)
-  if (existingPeriodId) {
-    return existingPeriodId
-  }
-
-  // No fiscal period exists - create one for the year of the transaction
-  const transactionDate = new Date(date)
-  const year = transactionDate.getFullYear()
-
-  const periodStart = `${year}-01-01`
-  const periodEnd = `${year}-12-31`
-
-  const { data, error } = await supabase
-    .from('fiscal_periods')
-    .upsert({
-      user_id: userId,
-      name: `Räkenskapsår ${year}`,
-      period_start: periodStart,
-      period_end: periodEnd,
-    }, {
-      onConflict: 'user_id,period_start,period_end',
-    })
-    .select('id')
-    .single()
-
-  if (error) {
-    console.error('Failed to create fiscal period:', error)
-    return null
-  }
-
-  return data?.id || null
-}
-
 /**
  * POST /api/transactions/[id]/match-invoice
  *
@@ -113,10 +70,10 @@ export async function POST(
     )
   }
 
-  // Fetch the invoice (validates ownership)
+  // Fetch the invoice with items (validates ownership, items needed for per-line VAT)
   const { data: invoice, error: fetchInvError } = await supabase
     .from('invoices')
-    .select('*, customer:customers(*)')
+    .select('*, customer:customers(*), items:invoice_items(*)')
     .eq('id', invoice_id)
     .eq('user_id', user.id)
     .single()
@@ -151,76 +108,23 @@ export async function POST(
   let journalEntryError: string | null = null
 
   try {
-    const fiscalPeriodId = await ensureFiscalPeriod(supabase, user.id, transaction.date)
-
-    if (fiscalPeriodId) {
-      let journalInput: CreateJournalEntryInput
-
-      if (accountingMethod === 'cash') {
-        // Kontantmetoden: combined revenue entry at payment
-        // Debit 1930 Företagskonto, Credit 30xx Försäljning, Credit 26xx Utgående moms
-        const revenueAccount = getRevenueAccount(invoice.vat_treatment as VatTreatment, entityType)
-        const lines: CreateJournalEntryInput['lines'] = [
-          {
-            account_number: '1930',
-            debit_amount: invoice.total,
-            credit_amount: 0,
-            line_description: `Inbetalning faktura ${invoice.invoice_number}`,
-          },
-          {
-            account_number: revenueAccount,
-            debit_amount: 0,
-            credit_amount: invoice.subtotal,
-            line_description: `Försäljning faktura ${invoice.invoice_number}`,
-          },
-        ]
-
-        if (invoice.vat_amount > 0) {
-          const vatAccount = getOutputVatAccount(invoice.vat_treatment as VatTreatment)
-          lines.push({
-            account_number: vatAccount,
-            debit_amount: 0,
-            credit_amount: invoice.vat_amount,
-            line_description: `Utgående moms faktura ${invoice.invoice_number}`,
-          })
-        }
-
-        journalInput = {
-          fiscal_period_id: fiscalPeriodId,
-          entry_date: transaction.date,
-          description: `Betalning faktura ${invoice.invoice_number} (kontantmetoden)`,
-          source_type: 'invoice_cash_payment',
-          source_id: invoice.id,
-          lines,
-        }
-      } else {
-        // Faktureringsmetoden: clear receivable
-        // Debit 1930 Företagskonto, Credit 1510 Kundfordringar
-        journalInput = {
-          fiscal_period_id: fiscalPeriodId,
-          entry_date: transaction.date,
-          description: `Betalning mottagen: Faktura ${invoice.invoice_number}`,
-          source_type: 'invoice_paid',
-          source_id: invoice.id,
-          lines: [
-            {
-              account_number: '1930',
-              debit_amount: paidAmount,
-              credit_amount: 0,
-              line_description: `Inbetalning faktura ${invoice.invoice_number}`,
-            },
-            {
-              account_number: '1510',
-              debit_amount: 0,
-              credit_amount: paidAmount,
-              line_description: `Faktura ${invoice.invoice_number} betald`,
-            },
-          ],
-        }
-      }
-
-      const journalEntry = await createJournalEntry(user.id, journalInput)
-      journalEntryId = journalEntry.id
+    if (accountingMethod === 'cash') {
+      // Kontantmetoden: combined revenue entry with per-line VAT rates
+      const journalEntry = await createInvoiceCashEntry(
+        user.id,
+        invoice as Invoice,
+        transaction.date,
+        entityType
+      )
+      journalEntryId = journalEntry?.id ?? null
+    } else {
+      // Faktureringsmetoden: clear receivable (Debit 1930, Credit 1510)
+      const journalEntry = await createInvoicePaymentJournalEntry(
+        user.id,
+        invoice as Invoice,
+        transaction.date
+      )
+      journalEntryId = journalEntry?.id ?? null
     }
   } catch (err) {
     console.error('Failed to create payment journal entry:', err)