fix(practice): correct route path for resume session

Change /practice/[studentId]/session to /practice/[studentId] since the
active session page is at the root [studentId] path, not a /session subfolder.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/app/practice/[studentId]/dashboard/DashboardClient.tsx

@@ -256,7 +256,7 @@ export function DashboardClient({
 
   // Handle resuming the current session
   const handleResumeSession = useCallback(() => {
-    router.push(`/practice/${studentId}/session`)
+    router.push(`/practice/${studentId}`)
   }, [studentId, router])
 
   return (