feat: add OpenEduCat institutional LMS features + Odoo 19 Backend SRS

- Update ENCOACH_UNIFIED_SRS.md with 6 new feature sections:
  Academic Year/Term, Departments, Admission/Enrollment,
  Subject Registration, Institutional Exams, Assignment Submissions
- Add TypeScript types: academic.ts, admission.ts, institutional-exam.ts
- Add API services: academic, admission, institutional-exam
- Add TanStack Query hooks: useAcademic, useAdmissions, useInstitutionalExams
- Add 9 new pages: AcademicYearManager, DepartmentManager, AdmissionList,
  AdmissionDetail, AdmissionRegisterPage, AdmissionApplication,
  SubjectRegistrationPage, InstitutionalExamSessions, MarksheetManager
- Update App.tsx routes, AdminLmsLayout sidebar (Institutional group),
  StudentLayout sidebar (Subject Registration)
- Generate ENCOACH_ODOO19_BACKEND_SRS.md: complete Odoo 19 backend spec
  covering 200+ REST API endpoints, 31 modules, all OpenEduCat models

Made-with: Cursor

src/components/StudentLayout.tsx

@@ -1,7 +1,7 @@
 import RoleLayout, { NavGroup } from "./RoleLayout";
 import {
   LayoutDashboard, BookOpen, ClipboardList, BarChart3,
-  CalendarCheck, Calendar, User, Target, GraduationCap,
+  CalendarCheck, Calendar, User, Target, GraduationCap, ListChecks,
 } from "lucide-react";
 
 const navGroups: NavGroup[] = [
@@ -10,6 +10,7 @@ const navGroups: NavGroup[] = [
     items: [
       { title: "Dashboard", url: "/student/dashboard", icon: LayoutDashboard },
       { title: "My Courses", url: "/student/courses", icon: BookOpen },
+      { title: "Subject Registration", url: "/student/subject-registration", icon: ListChecks },
       { title: "Assignments", url: "/student/assignments", icon: ClipboardList },
     ],
   },