feat: integrate audit logging across authentication, course management, and user operations

Add comprehensive audit trail tracking by integrating auditService throughout the application. Track user authentication (LOGIN, REGISTER), course lifecycle (CREATE, APPROVE_COURSE, REJECT_COURSE, ENROLL), content management (CREATE/DELETE Chapter/Lesson), file operations (UPLOAD_FILE, DELETE_FILE for videos and attachments), password management (CHANGE_PASSWORD, RESET_PASSWORD), user role updates (UPDATE

Backend/src/types/audit.types.ts

@@ -0,0 +1,65 @@
+import { AuditAction } from '@prisma/client';
+
+export interface CreateAuditLogParams {
+    userId?: number;
+    action: AuditAction;
+    entityType: string;
+    entityId?: number;
+    oldValue?: any;
+    newValue?: any;
+    ipAddress?: string;
+    userAgent?: string;
+    metadata?: any;
+}
+
+export interface AuditLogFilters {
+    userId?: number;
+    action?: AuditAction;
+    entityType?: string;
+    entityId?: number;
+    startDate?: Date;
+    endDate?: Date;
+    page?: number;
+    limit?: number;
+}
+
+export interface AuditLogResponse {
+    id: number;
+    user_id: number | null;
+    action: AuditAction;
+    entity_type: string;
+    entity_id: number | null;
+    old_value: any;
+    new_value: any;
+    ip_address: string | null;
+    user_agent: string | null;
+    metadata: any;
+    created_at: Date;
+    user?: {
+        id: number;
+        username: string;
+        email: string;
+    } | null;
+}
+
+export interface ListAuditLogsResponse {
+    data: AuditLogResponse[];
+    pagination: {
+        page: number;
+        limit: number;
+        total: number;
+        totalPages: number;
+    };
+}
+
+export interface AuditLogSummary {
+    action: AuditAction;
+    count: number;
+}
+
+export interface AuditLogStats {
+    totalLogs: number;
+    todayLogs: number;
+    actionSummary: AuditLogSummary[];
+    recentActivity: AuditLogResponse[];
+}