Add class numberOfSessions and fix attendance completion detection.

Sessions with full student attendance are now excluded from the pending list reliably by loading class rosters from the database.

components/classes/classModel.js

@@ -73,6 +73,11 @@ const classSchema = new mongoose.Schema({
     trim: true,
     default: ''
   },
+  numberOfSessions: {
+    type: Number,
+    min: 1,
+    default: null
+  },
   isActive: {
     type: Boolean,
     default: true

components/classes/classService.js

@@ -18,7 +18,7 @@ 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 isActive adminNotes createdAt updatedAt';
+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 normalizePricingFields = (body = {}) => {
   const tuitionFee = Math.max(0, Number(body.tuitionFee) || 0);
@@ -29,6 +29,13 @@ const normalizePricingFields = (body = {}) => {
   return { tuitionFee, hasDiscount, discount };
 };
 
+const normalizeNumberOfSessions = (value) => {
+  if (value === '' || value === null || value === undefined) return null;
+  const parsed = Number(value);
+  if (!Number.isFinite(parsed) || parsed < 1) return null;
+  return Math.floor(parsed);
+};
+
 const enrichClassForDisplay = (cls) => {
   const tuitionFee = cls.tuitionFee || 0;
   const discount = cls.hasDiscount ? (cls.discount || 0) : 0;
@@ -77,7 +84,11 @@ const getOne = async (id) => {
 };
 
 const create = async (body) => {
-  const payload = applyScheduleFields({ ...body, ...normalizePricingFields(body) }, body);
+  const payload = applyScheduleFields({
+    ...body,
+    ...normalizePricingFields(body),
+    numberOfSessions: normalizeNumberOfSessions(body.numberOfSessions)
+  }, body);
   if (body.freeSpots === '' || body.freeSpots === null || body.freeSpots === undefined) {
     payload.freeSpots = null;
   } else {
@@ -88,7 +99,13 @@ const create = async (body) => {
 };
 
 const update = async (id, body) => {
-  const payload = applyScheduleFields({ ...body, ...normalizePricingFields(body) }, body);
+  const payload = applyScheduleFields({
+    ...body,
+    ...normalizePricingFields(body),
+    ...(body.numberOfSessions !== undefined
+      ? { numberOfSessions: normalizeNumberOfSessions(body.numberOfSessions) }
+      : {})
+  }, body);
   if (body.freeSpots === '' || body.freeSpots === null) {
     payload.freeSpots = null;
   } else if (body.freeSpots !== undefined) {