feat(v3): restructure project + add complete frontend

- Restructure: move backend from new_project/ to backend/
- Add full React/TypeScript frontend (37 pages, 17 services, 16 type defs, 11 query hooks)
- Add docs/ with SRS specs, user stories, and workflow documentation
- Update .gitignore for new directory layout

Workflows implemented:
  WF1 User Signup, WF2 Placement Test, WF3 Exam Configuration,
  WF4 General English Exam, WF5 Course Generation,
  WF6 Entity Student Onboarding, AI Course Generation,
  Adaptive Learning Engine UI, White-Label Branding, Score Release

Made-with: Cursor

frontend/src/services/student-leave.service.ts

@@ -0,0 +1,33 @@
+import { api } from "@/lib/api-client";
+import type { StudentLeaveRequest, StudentLeaveType, StudentLeaveCreateRequest } from "@/types/student-leave";
+import type { PaginatedResponse, PaginationParams, ApiSuccessResponse } from "@/types";
+
+export const studentLeaveService = {
+  async listLeaves(params?: PaginationParams): Promise<PaginatedResponse<StudentLeaveRequest>> {
+    return api.get<PaginatedResponse<StudentLeaveRequest>>("/student-leaves", params as Record<string, string | number | boolean | undefined>);
+  },
+
+  async createLeave(data: StudentLeaveCreateRequest): Promise<StudentLeaveRequest> {
+    return api.post<StudentLeaveRequest>("/student-leaves", data);
+  },
+
+  async updateLeave(id: number, data: Partial<StudentLeaveCreateRequest>): Promise<StudentLeaveRequest> {
+    return api.patch<StudentLeaveRequest>(`/student-leaves/${id}`, data);
+  },
+
+  async approveLeave(id: number): Promise<StudentLeaveRequest> {
+    return api.post<StudentLeaveRequest>(`/student-leaves/${id}/approve`);
+  },
+
+  async rejectLeave(id: number): Promise<StudentLeaveRequest> {
+    return api.post<StudentLeaveRequest>(`/student-leaves/${id}/reject`);
+  },
+
+  async listLeaveTypes(params?: PaginationParams): Promise<PaginatedResponse<StudentLeaveType>> {
+    return api.get<PaginatedResponse<StudentLeaveType>>("/student-leave-types", params as Record<string, string | number | boolean | undefined>);
+  },
+
+  async createLeaveType(data: Pick<StudentLeaveType, "name">): Promise<StudentLeaveType> {
+    return api.post<StudentLeaveType>("/student-leave-types", data);
+  },
+};