Fix/supp ag fb (#1023)

* fix: prevent credit notes from entering payment flow

* fix: persist and display customer personal numbers

* feat: configure automatic invoice reminder days

* fix: issue credit notes through send flow

* chore: add repository agent guidance

* feat(mcp): route tools across user companies

* fix(articles): delete unused register entries

* feat(invoices): improve issued invoice actions

* feat(supplier-invoices): retain uploaded source documents

* docs: record implementation decisions

* feat: enhance customer personal number handling and validation

- Updated CustomerForm to allow personal numbers in the format of "********-1234" for individual customers.
- Added validation to ensure personal numbers are only accepted for individual customers in CreateCustomerSchema.
- Implemented masking and encryption for personal numbers to enhance data protection.
- Introduced new utility functions for masking and encrypting personal numbers.
- Added database migration to enforce unique constraints on credit note relationships and prevent duplicate entries.
- Enhanced error handling and logging for credit note issuance and invoice processing.
- Updated tests to cover new credit note creation guards and personal number handling.

* test: enhance list companies test with supabase query mocks

types/index.ts

@@ -313,6 +313,9 @@ export interface CompanySettings {
 
   // Automation
   send_invoice_reminders: boolean
+  reminder_days_level_1: number
+  reminder_days_level_2: number
+  reminder_days_level_3: number
 
   // Reminder surcharges (dröjsmålsränta + lagstadgad påminnelseavgift)
   reminder_fee_enabled: boolean
@@ -1157,7 +1160,7 @@ export interface CreateCustomerInput {
   country?: string
   org_number?: string
   vat_number?: string
-  personal_number?: string
+  personal_number?: string | null
   language?: 'sv' | 'en'
   default_payment_terms?: number
   notes?: string