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/import/sie/create-accounts/route.ts

@@ -71,27 +71,8 @@ export async function POST(request: Request) {
       return NextResponse.json({ error: 'No accounts provided' }, { status: 400 })
     }
 
-    // Fetch existing accounts to avoid duplicates
-    const { data: existingAccounts } = await supabase
-      .from('chart_of_accounts')
-      .select('account_number')
-      .eq('user_id', user.id)
-
-    const existingNumbers = new Set(existingAccounts?.map(a => a.account_number) || [])
-
-    // Filter to only accounts that don't exist
-    const newAccounts = accounts.filter(a => !existingNumbers.has(a.number))
-
-    if (newAccounts.length === 0) {
-      return NextResponse.json({
-        success: true,
-        created: 0,
-        message: 'All accounts already exist'
-      })
-    }
-
-    // Prepare accounts for insertion
-    const accountsToInsert = newAccounts.map(account => {
+    // Prepare accounts for upsert (idempotent — safe to retry)
+    const accountsToUpsert = accounts.map(account => {
       const accountClass = parseInt(account.number.charAt(0), 10) || 1
       const accountGroup = account.number.substring(0, 2)
       const accountType = getAccountType(account.number)
@@ -112,26 +93,32 @@ export async function POST(request: Request) {
       }
     })
 
-    // Insert in batches of 100 to avoid timeout
+    // Upsert in batches of 100 to avoid timeout
+    // ignoreDuplicates skips rows that already exist (no update)
     const batchSize = 100
     let totalCreated = 0
 
-    for (let i = 0; i < accountsToInsert.length; i += batchSize) {
-      const batch = accountsToInsert.slice(i, i + batchSize)
+    for (let i = 0; i < accountsToUpsert.length; i += batchSize) {
+      const batch = accountsToUpsert.slice(i, i + batchSize)
 
-      const { error } = await supabase
+      const { data: upserted, error } = await supabase
         .from('chart_of_accounts')
-        .insert(batch)
+        .upsert(batch, {
+          onConflict: 'user_id,account_number',
+          ignoreDuplicates: true,
+          count: 'exact',
+        })
+        .select('account_number')
 
       if (error) {
-        console.error('Error inserting accounts batch:', error)
+        console.error('Error upserting accounts batch:', error)
         return NextResponse.json({
           error: `Failed to create accounts: ${error.message}`,
           created: totalCreated,
         }, { status: 500 })
       }
 
-      totalCreated += batch.length
+      totalCreated += upserted?.length ?? batch.length
     }
 
     return NextResponse.json({

app/api/import/sie/execute/route.ts

@@ -1,4 +1,5 @@
 import { createClient } from '@/lib/supabase/server'
+import { fetchAllRows } from '@/lib/supabase/fetch-all'
 import { NextResponse } from 'next/server'
 import { parseSIEFile, detectEncoding, decodeBuffer } from '@/lib/import/sie-parser'
 import { suggestMappings } from '@/lib/import/account-mapper'
@@ -53,15 +54,18 @@ export async function POST(request: Request) {
     if (mappingsJson) {
       mappings = JSON.parse(mappingsJson)
     } else {
-      // Fetch user's chart of accounts and generate mappings
-      const { data: basAccounts } = await supabase
-        .from('chart_of_accounts')
-        .select('*')
-        .eq('user_id', user.id)
-        .eq('is_active', true)
-        .order('account_number')
+      // Fetch user's full chart of accounts (paginated to avoid 1000-row limit)
+      const basAccounts = await fetchAllRows(({ from, to }) =>
+        supabase
+          .from('chart_of_accounts')
+          .select('*')
+          .eq('user_id', user.id)
+          .eq('is_active', true)
+          .order('account_number')
+          .range(from, to)
+      )
 
-      if (!basAccounts || basAccounts.length === 0) {
+      if (basAccounts.length === 0) {
         return NextResponse.json({
           error: 'No chart of accounts found. Please complete onboarding first.',
         }, { status: 400 })

app/api/import/sie/parse/route.ts

@@ -1,4 +1,5 @@
 import { createClient } from '@/lib/supabase/server'
+import { fetchAllRows } from '@/lib/supabase/fetch-all'
 import { NextResponse } from 'next/server'
 import {
   parseSIEFile,
@@ -77,15 +78,18 @@ export async function POST(request: Request) {
       }, { status: 400 })
     }
 
-    // Fetch user's chart of accounts
-    const { data: basAccounts } = await supabase
-      .from('chart_of_accounts')
-      .select('*')
-      .eq('user_id', user.id)
-      .eq('is_active', true)
-      .order('account_number')
+    // Fetch user's full chart of accounts (paginated to avoid 1000-row limit)
+    const basAccounts = await fetchAllRows(({ from, to }) =>
+      supabase
+        .from('chart_of_accounts')
+        .select('*')
+        .eq('user_id', user.id)
+        .eq('is_active', true)
+        .order('account_number')
+        .range(from, to)
+    )
 
-    if (!basAccounts || basAccounts.length === 0) {
+    if (basAccounts.length === 0) {
       return NextResponse.json({
         error: 'No chart of accounts found. Please complete onboarding first.',
       }, { status: 400 })