feat: BAS data overhaul, currency revaluation, expenses, UI polish, and cleanup

- Update BAS account catalog with comprehensive SRU codes and K2 flags
- Add currency revaluation service with tests and API route
- Add expenses page and account deletion API
- Enhance booking templates with new patterns and improved tests
- Improve transaction categorization with template picker and description matching
- Polish dashboard, onboarding, import, and transaction UIs
- Refactor year-end service for multi-step closing
- Move SRU generator to ne-bilaga, remove standalone SRU export
- Remove unused dev docs, mock data, and extension hooks
- Add invoice delivery note sequences migration

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

app/api/settings/route.ts

@@ -38,7 +38,7 @@ export async function PUT(request: Request) {
   // Fetch current settings to check for tax-relevant changes
   const { data: oldSettings } = await supabase
     .from('company_settings')
-    .select('entity_type, moms_period, f_skatt, vat_registered, pays_salaries, fiscal_year_start_month')
+    .select('entity_type, moms_period, f_skatt, vat_registered, pays_salaries, fiscal_year_start_month, onboarding_complete')
     .eq('user_id', user.id)
     .single()
 
@@ -46,6 +46,12 @@ export async function PUT(request: Request) {
   if (!validation.success) return validation.response
   const body = validation.data
 
+  // Lock company_name and org_number after onboarding is complete
+  if (oldSettings && (oldSettings as Record<string, unknown>).onboarding_complete === true) {
+    delete (body as Record<string, unknown>).company_name
+    delete (body as Record<string, unknown>).org_number
+  }
+
   // Validate: enskild firma must use calendar year (BFL 3 kap.)
   const effectiveEntityType = body.entity_type || oldSettings?.entity_type
   const effectiveFYStartMonth = body.fiscal_year_start_month ?? oldSettings?.fiscal_year_start_month