Add 'approve without feedback' button for homework review

Curators/admins can mark a submission APPROVED (and complete the lesson)
without writing feedback. The student sees 'ДЗ принято ✓' and can no
longer resubmit. No email is sent on silent approval.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/student/homework-section.tsx

@@ -21,6 +21,7 @@ interface Submission {
   files: HWFile[];
   audioUrl?: string | null;
   submittedAt: Date;
+  status: string;
   feedbacks: Feedback[];
 }
 
@@ -47,6 +48,9 @@ export function HomeworkSection({ homework, submission, slug, lessonId, allowAud
   const [editing, setEditing] = useState(!submission);
 
   const isReviewed = submission && submission.feedbacks.length > 0;
+  const isApproved = submission?.status === "APPROVED";
+  // Финализировано: есть фидбек ИЛИ ДЗ принято кнопкой без ответа. Нельзя пересдавать.
+  const isLocked = Boolean(isReviewed || isApproved);
 
   const inputStyle = {
     border: "2px solid var(--border)",
@@ -138,8 +142,45 @@ export function HomeworkSection({ homework, submission, slug, lessonId, allowAud
         </div>
       )}
 
+      {/* Принято без письменного ответа */}
+      {isApproved && !isReviewed && submission && (
+        <div className="space-y-3">
+          <div className="flex items-center gap-2">
+            <span className="text-xs px-2 py-0.5 font-bold uppercase tracking-widest" style={{ border: "2px solid var(--foreground)", background: "var(--accent)" }}>
+              ДЗ принято ✓
+            </span>
+            <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
+              Сдано {new Date(submission.submittedAt).toLocaleDateString("ru-RU")}
+            </span>
+          </div>
+          {submission.text && (
+            <div className="px-4 py-3 text-sm whitespace-pre-wrap opacity-70" style={{ border: "2px solid var(--border)" }}>
+              {submission.text}
+            </div>
+          )}
+          {submission.audioUrl && (
+            <div className="px-4 py-2" style={{ border: "1px solid var(--border)" }}>
+              <p className="text-xs mb-1" style={{ color: "var(--muted-foreground)" }}>Аудио-ответ:</p>
+              <audio controls src={submission.audioUrl} style={{ height: 32, width: "100%" }} />
+            </div>
+          )}
+          {submission.files.length > 0 && (
+            <div className="space-y-1">
+              {submission.files.map((f) => (
+                <a key={f.url} href={f.url} target="_blank" rel="noopener noreferrer"
+                  className="flex items-center gap-2 px-3 py-2 text-xs" style={{ border: "2px solid var(--border)" }}>
+                  <span>📎</span>
+                  <span className="flex-1 underline">{f.name}</span>
+                  <span style={{ color: "var(--muted-foreground)" }}>{formatSize(f.size)}</span>
+                </a>
+              ))}
+            </div>
+          )}
+        </div>
+      )}
+
       {/* Submitted, pending review */}
-      {submission && !isReviewed && !editing && (
+      {submission && !isLocked && !editing && (
         <div className="space-y-3">
           <div className="flex items-center justify-between">
             <div className="flex items-center gap-2">
@@ -182,7 +223,7 @@ export function HomeworkSection({ homework, submission, slug, lessonId, allowAud
       )}
 
       {/* Form */}
-      {editing && !isReviewed && (
+      {editing && !isLocked && (
         <div className="space-y-3">
           <textarea
             value={text}