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

tests/helpers.ts

@@ -587,6 +587,9 @@ export function makeCompanySettings(
     invoice_footer_text: null,
     invoice_email_texts: null,
     send_invoice_reminders: true,
+    reminder_days_level_1: 15,
+    reminder_days_level_2: 30,
+    reminder_days_level_3: 45,
     reminder_fee_enabled: true,
     reminder_fee_amount: 60,
     reminder_interest_rate_override: null,