feat(getting-started): add anchor id to assembly video for deep linking

Add id="assembly-video" to video containers to enable direct linking
to the assembly video section (e.g., /getting-started#assembly-video)

src/pages/GettingStarted.jsx

@@ -255,6 +255,7 @@ export default function GettingStarted() {
               </Typography>
 
               <Box
+                id="assembly-video"
                 sx={{
                   position: 'relative',
                   paddingBottom: '56.25%',
@@ -398,6 +399,7 @@ export default function GettingStarted() {
               </Typography>
 
               <Box
+                id="assembly-video"
                 sx={{
                   position: 'relative',
                   paddingBottom: '56.25%',