feat: add pending student registration flow and pricing APIs.

Support public class lookup, user provisioning, installment pricing, and admin approval before final enrollment.

utils/registrationPricing.test.js

@@ -0,0 +1,46 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const {
+  calculateEnrollmentPricing,
+  calculateClassRequestPricing,
+  calculateMidpointDueDate
+} = require('./registrationPricing');
+
+test('full payment applies 500k discount', () => {
+  const result = calculateEnrollmentPricing(
+    { tuitionFee: 5_000_000, hasDiscount: false },
+    { sectionCount: 16 },
+    'full'
+  );
+  assert.equal(result.totalAmount, 4_500_000);
+  assert.equal(result.paymentDiscount, 500_000);
+  assert.equal(result.amountDueNow, 4_500_000);
+});
+
+test('installments charge full tuition with half due now', () => {
+  const result = calculateEnrollmentPricing(
+    { tuitionFee: 4_000_000, hasDiscount: false, startDate: '2026-09-01', days: [2, 4] },
+    { sectionCount: 16 },
+    'installments'
+  );
+  assert.equal(result.totalAmount, 4_000_000);
+  assert.equal(result.amountDueNow, 2_000_000);
+  assert.equal(result.secondInstallmentAmount, 2_000_000);
+  assert.ok(result.secondInstallmentDueDate);
+});
+
+test('class request deposit is 10 percent', () => {
+  const result = calculateClassRequestPricing({ tuitionFee: 3_000_000, hasDiscount: false });
+  assert.equal(result.amountDueNow, 300_000);
+  assert.equal(result.paymentPlan, 'deposit');
+});
+
+test('midpoint due date is halfway through course duration', () => {
+  const due = calculateMidpointDueDate(
+    { startDate: '2026-01-01', days: [2, 4] },
+    { sectionCount: 16 }
+  );
+  assert.equal(due.toISOString().slice(0, 10), '2026-01-29');
+});