Supp/invoice bfl errors (#390)

* feat(accounting): update accounting method validation and messaging for aktiebolag and enskild firma

* Remove AI subsystem and related code

- Deleted AI proposals and requests persistence logic from `lib/ai/proposals/persist.ts`.
- Removed re-validation logic for proposals in `lib/ai/proposals/re-validate.ts`.
- Cleaned up schemas related to AI flows in `lib/api/schemas.ts`.
- Removed AI-related fields from bookkeeping engine in `lib/bookkeeping/engine.ts`.
- Eliminated AI event types from `lib/events/types.ts`.
- Updated tests to reflect the removal of AI-related functionality in `lib/extensions/__tests__/sectors.test.ts`.
- Adjusted initialization logic in `lib/init.ts` to exclude AI proposal handler registration.
- Cleaned up transaction ingestion logic in `lib/transactions/ingest.ts` to remove AI flow checks.
- Updated helper functions in `tests/helpers.ts` to remove AI-related settings.
- Removed AI-related types and interfaces from `types/index.ts`.
- Added migration script to drop AI-related tables and settings from the database.

* fix(migrations): ensure foreign key constraint is dropped before removing AI tables

* feat(invoice-inbox): implement deterministic invoice field extraction and inbox provisioning

- Added `extract-invoice-fields.ts` for extracting fields from PDF invoices using regex and pdfjs-dist, replacing the previous AI classifier.
- Introduced `inbox-provisioning.ts` to manage company inbox addresses and rotation of inboxes using Supabase RPCs.
- Created `resend-inbound.ts` for handling inbound email events and attachments via the Resend API.
- Defined the extension manifest for the invoice inbox, specifying required environment variables and descriptions.
- Migrated database schema to remove AI-related columns and tighten the status enum in `invoice_inbox_items`.

* feat(invoice-inbox): remove AI-specific columns and tighten status enum

* fix(skattekonto): remove manual entry creation reference from transaction input

* fix(schemas): remove accounting method validation for aktiebolag in UpdateSettingsSchema

lib/company/__tests__/actions.test.ts

@@ -260,7 +260,7 @@ describe('createCompanyFromTicRole', () => {
     expect(settings.entity_type).toBe('enskild_firma')
     expect(settings.vat_registered).toBe(false)
     expect(settings.moms_period).toBeNull()
-    // EF entities default to cash per K1/BFNAR 2013:2; AB must use accrual (K2/K3).
+    // Default for EF is kontantmetoden (BFL 5 kap. 2 §); AB defaults to accrual but may switch.
     expect(settings.accounting_method).toBe('cash')
   })
 })

lib/company/actions.ts

@@ -303,11 +303,9 @@ export async function createCompanyFromTicRole(params: {
   // under SFL.
   const momsPeriod = vatRegistered ? 'quarterly' : null
 
-  // EF ≤3 MSEK may use kontantmetoden under K1/BFNAR 2013:2; above that
-  // threshold, BFNAR 2017:3 requires bokföringsmässiga grunder. We default
-  // to cash because the vast majority of EF users are small; users above
-  // the threshold can switch in /settings/bookkeeping. Aktiebolag must use
-  // accrual under K2/K3.
+  // Default by entity_type: EF → kontantmetoden, AB → faktureringsmetoden.
+  // Both forms may use either method under BFL 5 kap. 2 § when annual net
+  // turnover is normally ≤ 3 MSEK; users can change in /settings/bookkeeping.
   const accountingMethod = entityType === 'enskild_firma' ? 'cash' : 'accrual'
 
   const settings: Record<string, unknown> = {