refine: required confirmation_email field on both student forms, StudentEmail uses it directly

- Add dedicated 'confirmation_email' (type=email, required) field
  to student form at end of submission (partage + admin).
- ThesisCreateController now validates it is present and a valid
  email; form is rejected if missing/invalid.
- Autofocus mapping for confirmation_email errors.
- StudentEmail uses confirmation_email directly (removed extractEmail
  hack that mined email from free-form contact field).

app/src/Controllers/ThesisCreateController.php

@@ -173,6 +173,7 @@ class ThesisCreateController
         if (str_contains($message, 'langue'))               return 'languages';
         if (str_contains($message, 'mots-clés'))            return 'tag';
         if (str_contains($message, 'Lien URL'))             return 'lien';
+        if (str_contains($message, 'e-mail de confirmation')) return 'confirmation_email';
         return null;
     }
 
@@ -283,8 +284,18 @@ class ThesisCreateController
             }
         }
 
+        // Confirmation e-mail (required)
+        $confirmationEmail = trim($post['confirmation_email'] ?? '');
+        if ($confirmationEmail === '') {
+            throw new Exception("L'adresse e-mail de confirmation est requise.");
+        }
+        $confirmationEmail = filter_var($confirmationEmail, FILTER_VALIDATE_EMAIL);
+        if ($confirmationEmail === false) {
+            throw new Exception("L'adresse e-mail de confirmation n'est pas valide.");
+        }
+
         return compact(
-            'auteurName', 'mail', 'showContact', 'annee', 'orientationId', 'apProgramId',
+            'auteurName', 'mail', 'showContact', 'confirmationEmail', 'annee', 'orientationId', 'apProgramId',
             'finalityId', 'titre', 'subtitle', 'synopsis', 'durationInfo',
             'juryMembers', 'keywords', 'languageIds', 'formatIds',
             'licenseId', 'lien', 'accessTypeId'