Salary module (#245)

* feat: implement salary module with personnummer encryption, salary entries, tax tables, and AGI tracking

- Added personnummer encryption and decryption functions for secure storage.
- Created salary entries handling for journal entries including gross salary, tax withholding, and employer contributions.
- Implemented tax table lookup functionality for calculating tax amounts based on monthly income.
- Developed SQL migration for salary module including tables for payroll configuration, tax rates, employees, salary runs, salary run employees, salary line items, and AGI declarations.
- Established row-level security policies for all new tables to ensure company-scoped access.

* feat: add salary calculation modules for 2026

- Implemented engångsskatt calculation for one-time payments with tax brackets.
- Added löneväxling functionality for salary sacrifice to pension, including employer savings and warnings.
- Created pain.001 generator for salary batch payments in compliance with Swedish banking standards.
- Developed PDF template for payslips, including detailed breakdowns and employer costs.
- Generated seed data for Swedish tax tables for 2026, including SQL insert statements.
- Implemented traktamente calculations for per diem and mileage allowances, adhering to Skatteverket regulations.
- Added seed script for populating tax tables in the database.

* feat: Update meal reduction percentages in traktamente calculation

fix: Remove obsolete seed script for 2026 tax tables

feat: Extend SalaryRunStatus type to include 'corrected' status

feat: Implement KU10 XML generation endpoint for annual employee income statements

feat: Add endpoint for creating corrections to booked salary runs

feat: Implement endpoint for sending payslip PDFs to employees

feat: Create KU10 XML generator for annual reporting

feat: Add salary transaction matcher for auto-linking bank transactions to salary entries

chore: Add database migration for salary correction support

* feat: replace select elements with custom Select component for employment and salary types

* feat: enhance salary calculations with pension entry and avgifter category support

app/api/reports/avgifter-basis/route.ts

@@ -0,0 +1,28 @@
+import { createClient } from '@/lib/supabase/server'
+import { NextResponse } from 'next/server'
+import { requireCompanyId } from '@/lib/company/context'
+import { generateAvgifterBasis } from '@/lib/reports/avgifter-basis'
+
+/**
+ * Arbetsgivaravgiftsunderlag report.
+ * Monthly breakdown by avgifter rate category for AGI reconciliation.
+ * Per BFL: Part of räkenskapsinformation, 7-year retention.
+ */
+export async function GET(request: Request) {
+  const supabase = await createClient()
+  const { data: { user } } = await supabase.auth.getUser()
+  if (!user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const companyId = await requireCompanyId(supabase, user.id)
+
+  const { searchParams } = new URL(request.url)
+  const year = parseInt(searchParams.get('year') || new Date().getFullYear().toString())
+
+  try {
+    const report = await generateAvgifterBasis(supabase, companyId, year)
+    return NextResponse.json({ data: report })
+  } catch (err) {
+    const message = err instanceof Error ? err.message : 'Kunde inte generera avgiftsunderlag'
+    return NextResponse.json({ error: message }, { status: 500 })
+  }
+}

app/api/reports/salary-journal/route.ts

@@ -0,0 +1,29 @@
+import { createClient } from '@/lib/supabase/server'
+import { NextResponse } from 'next/server'
+import { requireCompanyId } from '@/lib/company/context'
+import { generateSalaryJournal } from '@/lib/reports/salary-journal'
+
+/**
+ * Lönejournal report — per BFNAR 2013:2 behandlingshistorik requirement.
+ * Monthly/annual per-employee salary register for AGI reconciliation.
+ */
+export async function GET(request: Request) {
+  const supabase = await createClient()
+  const { data: { user } } = await supabase.auth.getUser()
+  if (!user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const companyId = await requireCompanyId(supabase, user.id)
+
+  const { searchParams } = new URL(request.url)
+  const year = parseInt(searchParams.get('year') || new Date().getFullYear().toString())
+  const monthFrom = searchParams.get('month_from') ? parseInt(searchParams.get('month_from')!) : undefined
+  const monthTo = searchParams.get('month_to') ? parseInt(searchParams.get('month_to')!) : undefined
+
+  try {
+    const report = await generateSalaryJournal(supabase, companyId, year, monthFrom, monthTo)
+    return NextResponse.json({ data: report })
+  } catch (err) {
+    const message = err instanceof Error ? err.message : 'Kunde inte generera lönejournal'
+    return NextResponse.json({ error: message }, { status: 500 })
+  }
+}

app/api/reports/vacation-liability/route.ts

@@ -0,0 +1,28 @@
+import { createClient } from '@/lib/supabase/server'
+import { NextResponse } from 'next/server'
+import { requireCompanyId } from '@/lib/company/context'
+import { generateVacationLiability } from '@/lib/reports/vacation-liability'
+
+/**
+ * Semesterlöneskuld report — per BFNAR 2016:10 kap 16.
+ * Per-employee vacation liability (accounts 2920 + 2940).
+ * Required for year-end closing.
+ */
+export async function GET(request: Request) {
+  const supabase = await createClient()
+  const { data: { user } } = await supabase.auth.getUser()
+  if (!user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const companyId = await requireCompanyId(supabase, user.id)
+
+  const { searchParams } = new URL(request.url)
+  const year = parseInt(searchParams.get('year') || new Date().getFullYear().toString())
+
+  try {
+    const report = await generateVacationLiability(supabase, companyId, year)
+    return NextResponse.json({ data: report })
+  } catch (err) {
+    const message = err instanceof Error ? err.message : 'Kunde inte generera semesterlöneskuld'
+    return NextResponse.json({ error: message }, { status: 500 })
+  }
+}