feat: implement core course platform UI and logic

- Add project configuration and git ignore rules
- Implement App router with protected routes
- Develop course player, grid, and card components
- Add state management for course progress and navigation
- Initialize database services for course and comment data

types.ts

@@ -0,0 +1,66 @@
+export type SectionVariant = 'landscape' | 'portrait';
+
+export type AttachmentType = 'pdf' | 'spreadsheet' | 'zip' | 'doc' | 'image' | 'link' | 'video';
+
+export interface Attachment {
+  id: string;
+  name: string;
+  type: AttachmentType;
+  url: string;
+  size?: string; // e.g. "4.2 MB"
+  description?: string;
+  lessonId?: string; // Associated lesson or global course asset
+  downloadCount?: number;
+}
+
+export interface Lesson {
+  id: string;
+  title: string;
+  duration: string;
+  videoUrl: string;
+  isFree: boolean; // true = Public, false = Pro (Login required)
+  description?: string;
+  attachments?: Attachment[]; // Lesson-specific downloadable materials
+}
+
+export interface Course {
+  id: string;
+  title: string;
+  category: string;
+  thumbnail: string;
+  lessons: Lesson[]; 
+  progress?: number; // 0 to 100
+  views?: number;
+  duration: string; // Total duration or lesson count
+  description: string;
+  instructor?: string;
+  instructorRole?: string;
+  tips?: string[]; // Key takeaways / instructor tips
+  attachments?: Attachment[]; // Downloadable materials across entire course
+}
+
+export interface Section {
+  title: string;
+  variant: SectionVariant;
+  courses: Course[];
+}
+
+export type UserRole = 'professor' | 'student';
+
+export interface User {
+  email: string;
+  name: string;
+  role: UserRole;
+  avatar?: string;
+}
+
+export interface Comment {
+  id: string;
+  courseId: string;
+  lessonId?: string;
+  user: string;
+  text: string;
+  date: string;
+  reply?: string; // Professor's reply
+  replyDate?: string;
+}