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/lesson.service.ts

@@ -0,0 +1,21 @@
+import { api } from "@/lib/api-client";
+import type { Lesson, LessonCreateRequest } from "@/types/lesson";
+import type { PaginatedResponse, PaginationParams, ApiSuccessResponse } from "@/types";
+
+export const lessonService = {
+  async listLessons(params?: PaginationParams): Promise<PaginatedResponse<Lesson>> {
+    return api.get<PaginatedResponse<Lesson>>("/lessons", params as Record<string, string | number | boolean | undefined>);
+  },
+
+  async createLesson(data: LessonCreateRequest): Promise<Lesson> {
+    return api.post<Lesson>("/lessons", data);
+  },
+
+  async updateLesson(id: number, data: Partial<LessonCreateRequest>): Promise<Lesson> {
+    return api.patch<Lesson>(`/lessons/${id}`, data);
+  },
+
+  async deleteLesson(id: number): Promise<ApiSuccessResponse> {
+    return api.delete<ApiSuccessResponse>(`/lessons/${id}`);
+  },
+};