feat(selfpaced): student-facing My Programs dashboard

- ProgramsTab.jsx: Active/Completed programs, real progress, deterministic Continue Learning
  (reuses the same launch/poll pattern MyLearningTab already established), entitlement-blocked
  states shown with a real reason, never a silent dead end.
- StudentDashboard.jsx: new My Programs tab. api.js: programs/program/launchProgram.

frontend/src/platform/StudentDashboard.jsx

@@ -8,9 +8,11 @@ import CapstoneTab from './CapstoneTab'
 import AchievementsTab from './AchievementsTab'
 import ClassroomTab from './ClassroomTab'
 import ProfileTab from './ProfileTab'
+import ProgramsTab from './ProgramsTab'
 
 const TABS = [
   { key: 'learning', label: 'My Learning' },
+  { key: 'programs', label: 'My Programs' },
   { key: 'classroom', label: 'Classroom' },
   { key: 'practice', label: 'Practice' },
   { key: 'assessments', label: 'Assessments' },
@@ -45,6 +47,7 @@ export default function StudentDashboard({ student, onLogout }) {
       </nav>
 
       {tab === 'learning' && <MyLearningTab />}
+      {tab === 'programs' && <ProgramsTab />}
       {tab === 'classroom' && <ClassroomTab />}
       {tab === 'practice' && <PracticeTab />}
       {tab === 'assessments' && <AssessmentsTab />}