Add lesson content editor, quiz test endpoint, and lesson update API

- Backend: UpdateLesson handler (PUT /lessons/:id) for editing title, content, quiz questions
- Backend: TestQuiz handler (POST /lessons/:id/quiz-test) for quiz evaluation without enrollment
- Frontend: Content editor with markdown textarea, save, and approve-for-video workflow
- Frontend: Fix quiz endpoint to /lessons/:id/quiz-test

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ai-compliance-sdk/cmd/server/main.go

@@ -481,6 +481,10 @@ func main() {
 			// Quiz
 			academyRoutes.POST("/courses/:id/quiz", academyHandlers.SubmitQuiz)
 
+			// Lessons
+			academyRoutes.PUT("/lessons/:id", academyHandlers.UpdateLesson)
+			academyRoutes.POST("/lessons/:id/quiz-test", academyHandlers.TestQuiz)
+
 			// Statistics
 			academyRoutes.GET("/stats", academyHandlers.GetStatistics)