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

lib/api/__tests__/schemas.test.ts

@@ -1410,6 +1410,24 @@ describe('UpdateSettingsSchema', () => {
     })
   })
 
+  describe('reminder day thresholds', () => {
+    it('accepts integer thresholds from 1 through 365', () => {
+      const result = UpdateSettingsSchema.safeParse({
+        reminder_days_level_1: 7,
+        reminder_days_level_2: 21,
+        reminder_days_level_3: 365,
+      })
+
+      expect(result.success).toBe(true)
+    })
+
+    it.each([0, 366, 1.5])('rejects invalid threshold %s', (days) => {
+      const result = UpdateSettingsSchema.safeParse({ reminder_days_level_1: days })
+
+      expect(result.success).toBe(false)
+    })
+  })
+
   describe('invoice_email_texts', () => {
     it('accepts a valid nested partial', () => {
       const result = UpdateSettingsSchema.safeParse({