Add professor share calculation and financial reporting feature

Introduces per-class payout configuration (percentage or hourly rate,
plus an optional per-session expense allowance), pure calculation
utilities for professor payout/net profit/receivables, and a new
financial-reports API surface with per-class, per-session, and
date-range/monthly reports. Also adds full CRUD for institutional
expenses used in the range report, and wires up the new permissions
and roles. Fixes a pre-existing ReferenceError (missing
parseImportDate import) in paymentService that blocked creating
payments with dated transactions.

components/classes/classService.js

@@ -19,7 +19,7 @@ const applyScheduleFields = (payload, body) => {
   return payload;
 };
 
-const CLASS_LIST_FIELDS = 'name course professor students capacity tuitionFee hasDiscount discount freeSpots showOnFrontend startDate endDate days startTime endTime numberOfSessions isActive adminNotes createdAt updatedAt';
+const CLASS_LIST_FIELDS = 'name course professor students capacity tuitionFee hasDiscount discount freeSpots showOnFrontend startDate endDate days startTime endTime numberOfSessions payoutType payoutPercentage payoutHourlyRate extraExpensePerSession isActive adminNotes createdAt updatedAt';
 
 const normalizePricingFields = (body = {}) => {
   const tuitionFee = Math.max(0, Number(body.tuitionFee) || 0);
@@ -30,6 +30,14 @@ const normalizePricingFields = (body = {}) => {
   return { tuitionFee, hasDiscount, discount };
 };
 
+const normalizePayoutFields = (body = {}) => {
+  const payoutType = body.payoutType === 'hourly' ? 'hourly' : 'percentage';
+  const payoutPercentage = Math.min(100, Math.max(0, Number(body.payoutPercentage) || 0));
+  const payoutHourlyRate = Math.max(0, Number(body.payoutHourlyRate) || 0);
+  const extraExpensePerSession = Math.max(0, Number(body.extraExpensePerSession) || 0);
+  return { payoutType, payoutPercentage, payoutHourlyRate, extraExpensePerSession };
+};
+
 const normalizeNumberOfSessions = (value) => {
   if (value === '' || value === null || value === undefined) return null;
   const parsed = Number(value);
@@ -65,7 +73,7 @@ const getAll = async (query) => {
   const [items, total] = await Promise.all([
     Class.find(filter)
       .select(CLASS_LIST_FIELDS)
-      .populate({ path: 'course', select: 'title type price' })
+      .populate({ path: 'course', select: 'title type price sectionCount hoursPerSection' })
       .populate({ path: 'professor', select: 'name surname' })
       .skip(skip).limit(limit).sort({ createdAt: -1 }).lean(),
     Class.countDocuments(filter)
@@ -76,7 +84,7 @@ const getAll = async (query) => {
 
 const getOne = async (id) => {
   const cls = await Class.findById(id)
-    .populate({ path: 'course', select: 'title type price' })
+    .populate({ path: 'course', select: 'title type price sectionCount hoursPerSection' })
     .populate({ path: 'professor', select: 'name surname phoneNumber' })
       .populate({ path: 'students', select: 'name phoneNumber gender' })
     .lean();
@@ -88,6 +96,7 @@ const create = async (body) => {
   const payload = applyScheduleFields({
     ...body,
     ...normalizePricingFields(body),
+    ...normalizePayoutFields(body),
     numberOfSessions: normalizeNumberOfSessions(body.numberOfSessions)
   }, body);
   if (body.freeSpots === '' || body.freeSpots === null || body.freeSpots === undefined) {
@@ -103,6 +112,7 @@ const update = async (id, body) => {
   const payload = applyScheduleFields({
     ...body,
     ...normalizePricingFields(body),
+    ...normalizePayoutFields(body),
     ...(body.numberOfSessions !== undefined
       ? { numberOfSessions: normalizeNumberOfSessions(body.numberOfSessions) }
       : {})