fix(dashboard): use learner view for lesson lock empty states (#764)

Lock checks gated on isOrgStudent missed org-site students where
isStudentExperience is true but org role may be unset. Introduce
isCourseLearnerView (student experience OR org student) and mirror
the exercise page branch structure so locked lessons always show
StudentContentLockedNotice instead of the teacher empty state.

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Rotimi Best <rotimi-best@users.noreply.github.com>

apps/dashboard/src/routes/(app)/courses/[id]/+layout.svelte

@@ -25,7 +25,7 @@
   import { page } from '$app/state';
   import { profile } from '$lib/utils/store/user';
   import { isOrgAdmin } from '$lib/utils/store/org';
-  import { isOrgStudent } from '$lib/utils/store/app';
+  import { isCourseLearnerView } from '$lib/utils/store/app';
   import { t } from '$lib/utils/functions/translations';
   import { ContentType } from '@cio/utils/constants/content';
   import type { CourseMember } from '$features/course/utils/types';
@@ -104,7 +104,7 @@
   const showContentAskAiBar = $derived(
     isCourseReady &&
       isLessonOrExercisePage &&
-      !($isOrgStudent && isContentLockedForStudent) &&
+      !($isCourseLearnerView && isContentLockedForStudent) &&
       sidePanel.activePanelId !== AI_ASSISTANT_PANEL_ID
   );