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/invoices/__tests__/reminder-processor.test.ts

@@ -39,6 +39,7 @@ import {
   determineReminderLevel,
   calculateDaysOverdue,
 } from '../reminder-processor'
+import { getReminderDaysConfig } from '@/lib/email/reminder-templates'
 
 describe('determineReminderLevel', () => {
   it('returns null below the level-1 threshold', () => {
@@ -60,6 +61,37 @@ describe('determineReminderLevel', () => {
   it('returns null when all levels have been sent', () => {
     expect(determineReminderLevel(60, [1, 2, 3])).toBeNull()
   })
+
+  it('uses a company-specific schedule', () => {
+    const config = { 1: 7, 2: 21, 3: 35 } as const
+
+    expect(determineReminderLevel(6, [], config)).toBeNull()
+    expect(determineReminderLevel(7, [], config)).toBe(1)
+    expect(determineReminderLevel(21, [1], config)).toBe(2)
+    expect(determineReminderLevel(35, [1, 2], config)).toBe(3)
+  })
+})
+
+describe('getReminderDaysConfig', () => {
+  it('returns the existing defaults when no company settings are supplied', () => {
+    expect(getReminderDaysConfig()).toEqual({ 1: 15, 2: 30, 3: 45 })
+  })
+
+  it('returns configured company thresholds', () => {
+    expect(getReminderDaysConfig({
+      reminder_days_level_1: 5,
+      reminder_days_level_2: 10,
+      reminder_days_level_3: 20,
+    })).toEqual({ 1: 5, 2: 10, 3: 20 })
+  })
+
+  it('falls back to defaults for an invalid stored schedule', () => {
+    expect(getReminderDaysConfig({
+      reminder_days_level_1: 30,
+      reminder_days_level_2: 20,
+      reminder_days_level_3: 45,
+    })).toEqual({ 1: 15, 2: 30, 3: 45 })
+  })
 })
 
 describe('calculateDaysOverdue', () => {