feat: improve LMS course discovery and enrollment UX

- Add paginated recommended courses to LMS dashboard (top 3, list
    view)
    and explore page (12 per page); exclude courses blocking new
    students
  - Polish course preview modal: remove padding, render requirements as
    HTML, round banner image, secondary close button
  - Redirect to course start page after successful enrollment instead of
    /lms;
    keep spinner active until navigation completes
  - Auto-enable "allow new students" when a course is published
  - Move Explore after My Learning in LMS sidebar nav
  - Move Certificates after Content in course sidebar
  - Add hiddenColumns prop to CourseListRow; show "Learn more" button
    instead of actions menu in LMS explore context

apps/api/src/services/course/invite.ts

@@ -649,7 +649,7 @@ export async function enrollInCourse(
     return {
       success: true,
       alreadyJoined: true,
-      redirectTo: '/lms'
+      redirectTo: `/courses/${courseId}/lessons?next=true`
     };
   }
 
@@ -692,7 +692,7 @@ export async function enrollInCourse(
   return {
     success: true,
     alreadyJoined: false,
-    redirectTo: '/lms'
+    redirectTo: `/courses/${courseId}/lessons?next=true`
   };
 }
 
@@ -1056,6 +1056,6 @@ export async function acceptStudentInvite(token: string, user: TAuthUser, contex
   return {
     success: true,
     alreadyJoined: result.alreadyJoined,
-    redirectTo: '/lms'
+    redirectTo: `/courses/${result.courseId}/lessons?next=true`
   };
 }