Bug/momsdeklaration skv (#449)

* fix(salary): show birthdate in masked personnummer, hide the 4-digit suffix

Flip the personnummer display format from XXXXXXXX-NNNN to YYYYMMDD-XXXX so
the sensitive 4-digit suffix is hidden while the (public) birthdate stays
visible. Affects the employees list/detail, salary run, payslip PDF, payslip
email, and the MCP server tools (list_employees, get_salary_run). Each call
site now decrypts the stored personnummer before masking.

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

* fix(transactions): allow deleting unbooked transactions from "Alla transaktioner"

The history list only let users delete via the inbox card; once a category or
mall was picked but the verifikation hadn't been created, the row showed
"Ej bokförd" with no way to remove it. The API already permits delete while
journal_entry_id is null, so the gap was purely a missing UI affordance.

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

* fix(vat): populate ruta 20-24 for reverse charge + dishonest "Validera OK"

Three connected issues caused Skatteverket to reject momsdeklarationer
with FK004 even after our local "Validera"-knapp returned OK.

1. supplier-invoice-entries booked fiktiv moms (2614/2624/2634 + 2645/2647)
   on reverse-charge invoices but never the underlying basbelopp on 44xx/45xx.
   Ruta 30-32 filled up at SKV while ruta 20-24 stayed at 0 — SKV's FK004
   ("silent netting prohibited", ML 13 kap kräver båda sidor).

   Fix: generateReverseChargeBasisLines in vat-entries.ts emits parallel
   45xx/44xx debit + 4598 motkonto credit per rate group. Engine calls it
   from registration, cash, and credit-note paths. Skipped when the user
   booked the expense directly on a basis account to avoid double-counting.
   4598 added to BAS reference (no migration needed; account_number is
   plain text on journal_entry_lines).

2. rutorToMomsuppgift rounded each ruta independently but computed
   summaMoms from the unrounded ruta49. SKV recomputes the sum from
   integer rutor on their side, so fractional öres caused ±1 SEK drift
   and SKV rejected with FK009.

   Fix: derive summaMoms from the already-rounded VAT-amount rutor.

3. "Validera"-knappen only confirmed SKV's internal arithmetic — a
   declaration with ruta 30-32 populated and ruta 20-24 empty validated
   fine until /utkast hit FK004. Users got a false green light.

   Fix: vat-declaration-checks.ts runs locally before the SKV call,
   blocks Validera/Spara when ERROR-level findings exist, and surfaces
   them in a separate "Lokala kontroller"-section. Success message
   reworded so SKV's OK is no longer presented as filing-ready.

Tests: 4535/4536/4531/4425 lines + 4598 motkonto on EU/non-EU/byggtjänster
RC, credit-note reversal, fractional-öres summaMoms, all four pre-flight
codes (RC_BASIS_MISSING, RC_OUTPUT_MISSING, RC_INPUT_VAT_MISMATCH,
SUMMA_MOMS_DRIFT).

Backfill for already-posted entries follows in the next commit.

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

* feat: add skattekonto matching functionality

- Enhance TransactionInboxCard to display a warning for potential 1930↔1630 transfers.
- Implement match suggestions for skattekonto transactions in the backend.
- Create SkattekontoMatchDialog component for linking skattekonto rows to existing journal entries.
- Develop SkattekontoInboxCard component to handle skattekonto transactions in the inbox.
- Introduce skattekonto-match utility functions for candidate matching and linking.
- Update types to include match suggestions and enriched transaction responses.

* refactor: reorganize skattekonto types and implement bank counterpart matching logic

* docs: update CLAUDE.md to streamline integrations and clarify architecture details

* refactor: enhance reverse charge logic to handle non-basis accounts and prevent double-counting

---------

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

lib/salary/__tests__/personnummer.test.ts

@@ -80,8 +80,12 @@ describe('calculateAgeAtYearStart', () => {
 })
 
 describe('maskPersonnummer', () => {
-  it('masks with XXXXXXXX-XXXX format', () => {
-    expect(maskPersonnummer('9802')).toBe('XXXXXXXX-9802')
+  it('shows birthdate and masks the 4-digit suffix', () => {
+    expect(maskPersonnummer('199001019802')).toBe('19900101-XXXX')
+  })
+
+  it('strips non-digits before masking', () => {
+    expect(maskPersonnummer('19900101-9802')).toBe('19900101-XXXX')
   })
 })
 

lib/salary/pdf/payslip-template.tsx

@@ -203,7 +203,7 @@ export interface PayslipData {
 
   // Employee
   employeeName: string
-  personnummerMasked: string // XXXXXXXX-XXXX
+  personnummerMasked: string // YYYYMMDD-XXXX
   employmentType: string
 
   // Period

lib/salary/personnummer.ts

@@ -151,10 +151,11 @@ export function calculateAgeAtYearStart(personnummer: string, year: number): num
 }
 
 /**
- * Mask personnummer for display: XXXXXXXX-XXXX
+ * Mask personnummer for display: YYYYMMDD-XXXX (birthdate visible, suffix hidden).
  */
-export function maskPersonnummer(last4: string): string {
-  return `XXXXXXXX-${last4}`
+export function maskPersonnummer(personnummer: string): string {
+  const digits = personnummer.replace(/\D/g, '')
+  return `${digits.slice(0, 8)}-XXXX`
 }
 
 /**