fix(a11y): promote teacher page headings from h2 to h1

Dashboard, Courses, and Templates pages all used <h2> as their top-level
heading with no <h1> above them, breaking document outline and SEO.
Styling is unchanged (same Tailwind classes).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: guillermoscript

app/[locale]/dashboard/teacher/courses/page.tsx

@@ -50,9 +50,9 @@ export default async function TeacherCoursesPage() {
         <div className="flex-1 space-y-6 p-6 lg:p-8" data-testid="teacher-courses-list">
             <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
                 <div>
-                    <h2 className="text-2xl font-bold tracking-tight text-foreground">
+                    <h1 className="text-2xl font-bold tracking-tight text-foreground">
                         {t('title')}
-                    </h2>
+                    </h1>
                     <p className="text-sm text-muted-foreground mt-0.5">
                         {t('description')}
                     </p>

app/[locale]/dashboard/teacher/page.tsx

@@ -113,11 +113,11 @@ export default async function TeacherDashboard() {
 
       <div data-tour="teacher-welcome" className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
         <div>
-          <h2 className="text-2xl font-bold tracking-tight text-foreground" data-testid="teacher-welcome">
+          <h1 className="text-2xl font-bold tracking-tight text-foreground" data-testid="teacher-welcome">
             {t.rich('welcome', {
               userName: profile?.full_name?.split(' ')[0] || t('defaultName')
             })}
-          </h2>
+          </h1>
           <p className="text-sm text-muted-foreground mt-0.5">
             {t('subtitle')}
           </p>

app/[locale]/dashboard/teacher/templates/page.tsx

@@ -122,7 +122,7 @@ export default function PromptTemplatesPage() {
     <div className="flex-1 space-y-6 p-6 lg:p-8" data-testid="templates-page">
       <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
         <div>
-          <h2 className="text-2xl font-bold tracking-tight">{t('title')}</h2>
+          <h1 className="text-2xl font-bold tracking-tight">{t('title')}</h1>
           <p className="text-sm text-muted-foreground mt-0.5">
             {t('description')}
           </p>