Refactor CourseNavigation component by removing the unused ModuleData interface. Update MarkdownRenderer to ensure proper handling of architecture diagram images by checking the type of the src variable.

Author: vukrosic

components/course-navigation.tsx

@@ -12,13 +12,6 @@ interface LessonItem {
   href: string;
 }
 
-interface ModuleData {
-  title: string;
-  titleZh: string;
-  icon: React.ReactNode;
-  lessons: LessonItem[];
-}
-
 export function CourseNavigation() {
   const { language } = useLanguage();
   const pathname = usePathname();

components/markdown-renderer.tsx

@@ -107,7 +107,7 @@ export function MarkdownRenderer({ content }: MarkdownRendererProps) {
             if (!src) return null;
 
             // Check if this is the architecture diagram that should be smaller
-            const isArchitectureDiagram = alt?.includes('Architecture') || src?.includes('architecture');
+            const isArchitectureDiagram = alt?.includes('Architecture') || (typeof src === 'string' && src.includes('architecture'));
             const imageClassName = isArchitectureDiagram ? "w-1/2 h-auto mx-auto" : "w-full h-auto";
 
             // Handle external images