fix(lessons): fix lesson completion toggle, progress tracking, and XP toast

- Add missing DELETE RLS policy on lesson_completions so students can un-complete lessons
- Remove invalid tenant_id filter on lesson_completions query (table has no tenant_id column), fixing sidebar progress always showing 0%
- Fix i18n namespace from 'gamification' to 'components.gamification' for XP award toast
- Add error handling on insert/delete operations with user-facing error toasts

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: guillermoscript

app/[locale]/dashboard/student/courses/[courseId]/lessons/[lessonId]/lesson-navigation.tsx

@@ -38,7 +38,7 @@ export function LessonNavigation({
   requireSequentialCompletion = false,
 }: LessonNavigationProps) {
   const t = useTranslations('components.lessonNavigation')
-  const tGamification = useTranslations('gamification')
+  const tGamification = useTranslations('components.gamification')
   const [loading, setLoading] = useState(false)
   const [completed, setCompleted] = useState(isCompleted)
   const [certificateCode, setCertificateCode] = useState<string | null>(null)
@@ -59,21 +59,35 @@ export function LessonNavigation({
     }
 
     if (completed) {
-      await supabase
+      const { error } = await supabase
         .from('lesson_completions')
         .delete()
         .eq('lesson_id', lessonId)
         .eq('user_id', user.id)
 
+      if (error) {
+        console.error('Failed to uncomplete lesson:', error)
+        toast.error('Failed to update lesson status')
+        setLoading(false)
+        return
+      }
+
       setCompleted(false)
       setLoading(false)
       startTransition(() => { router.refresh() })
     } else {
-      await supabase.from('lesson_completions').insert({
+      const { error } = await supabase.from('lesson_completions').insert({
         lesson_id: lessonId,
         user_id: user.id,
       })
 
+      if (error) {
+        console.error('Failed to complete lesson:', error)
+        toast.error('Failed to mark lesson as complete')
+        setLoading(false)
+        return
+      }
+
       setCompleted(true)
       setLoading(false)
       toast.success(tGamification('xpAwarded.lesson_completion'))

app/[locale]/dashboard/student/courses/[courseId]/lessons/[lessonId]/page.tsx

@@ -179,8 +179,7 @@ export default async function LessonPage({ params }: PageProps) {
     supabase
       .from('lesson_completions')
       .select('lesson_id')
-      .eq('user_id', userId)
-      .eq('tenant_id', tenantId),
+      .eq('user_id', userId),
     supabase
       .from('lesson_resources')
       .select('id, file_name, file_size, mime_type')

supabase/migrations/20260330000000_add_lesson_completions_delete_policy.sql

@@ -0,0 +1,6 @@
+-- Add missing DELETE policy on lesson_completions
+-- Students need to be able to un-complete lessons (toggle)
+CREATE POLICY "Students can delete own completions"
+ON lesson_completions
+FOR DELETE
+USING (auth.uid() = user_id);