Add lesson progress tracking

- Toggle lesson completion via server action (LessonProgress table)
- "Отметить как пройденный" button on lesson page, turns accent when done
- Course sidebar: progress bar, checkmarks on completed lessons, X/Y counter per module
- Dashboard: progress bar on each course card with completion percentage

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

src/app/(student)/dashboard/page.tsx

@@ -14,7 +14,12 @@ export default async function StudentDashboard() {
       course: {
         include: {
           modules: {
-            include: { _count: { select: { lessons: true } } },
+            include: {
+              lessons: {
+                where: { published: true },
+                select: { id: true },
+              },
+            },
           },
           _count: { select: { modules: true } },
         },
@@ -27,6 +32,18 @@ export default async function StudentDashboard() {
   const active = enrollments.filter((e) => !e.expiresAt || e.expiresAt > now);
   const expired = enrollments.filter((e) => e.expiresAt && e.expiresAt <= now);
 
+  // Fetch progress for all lessons in active courses
+  const allLessonIds = active.flatMap((e) =>
+    e.course.modules.flatMap((m) => m.lessons.map((l) => l.id))
+  );
+  const progressRecords = allLessonIds.length > 0
+    ? await prisma.lessonProgress.findMany({
+        where: { userId: session.user.id, lessonId: { in: allLessonIds } },
+        select: { lessonId: true },
+      })
+    : [];
+  const completedSet = new Set(progressRecords.map((p) => p.lessonId));
+
   return (
     <main className="max-w-4xl mx-auto px-6 py-10 w-full">
       <h1 className="text-2xl font-bold mb-1">Мои курсы</h1>
@@ -45,7 +62,14 @@ export default async function StudentDashboard() {
       ) : (
         <div className="grid gap-4 sm:grid-cols-2">
           {active.map(({ course, expiresAt }) => {
-            const totalLessons = course.modules.reduce((s, m) => s + m._count.lessons, 0);
+            const totalLessons = course.modules.reduce((s, m) => s + m.lessons.length, 0);
+            const completedLessons = course.modules
+              .flatMap((m) => m.lessons)
+              .filter((l) => completedSet.has(l.id)).length;
+            const progressPct = totalLessons > 0
+              ? Math.round((completedLessons / totalLessons) * 100)
+              : 0;
+
             return (
               <Link
                 key={course.id}
@@ -60,23 +84,46 @@ export default async function StudentDashboard() {
                     📚
                   </div>
                 )}
-                <div className="p-4 flex-1">
+                <div className="p-4 flex-1 flex flex-col gap-2">
                   <h2 className="font-bold text-base leading-tight">{course.title}</h2>
                   {course.description && (
-                    <p className="text-xs mt-1 line-clamp-2" style={{ color: "var(--muted-foreground)" }}>
+                    <p className="text-xs line-clamp-2" style={{ color: "var(--muted-foreground)" }}>
                       {course.description}
                     </p>
                   )}
-                  <div className="flex items-center justify-between mt-3">
-                    <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
-                      {course._count.modules} модулей · {totalLessons} уроков
-                    </span>
-                    {expiresAt && (
-                      <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
-                        до {new Date(expiresAt).toLocaleDateString("ru-RU")}
-                      </span>
-                    )}
-                  </div>
+
+                  {/* Progress bar */}
+                  {totalLessons > 0 && (
+                    <div className="mt-auto">
+                      <div className="flex items-center justify-between mb-1">
+                        <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
+                          {completedLessons} из {totalLessons} уроков
+                        </span>
+                        <span
+                          className="text-xs font-bold"
+                          style={{ color: progressPct === 100 ? "var(--foreground)" : "var(--muted-foreground)" }}
+                        >
+                          {progressPct === 100 ? "✓ Завершён" : `${progressPct}%`}
+                        </span>
+                      </div>
+                      <div className="h-1.5 w-full" style={{ background: "var(--border)" }}>
+                        <div
+                          className="h-full transition-all"
+                          style={{
+                            width: `${progressPct}%`,
+                            background: progressPct === 100 ? "var(--foreground)" : "var(--accent)",
+                            border: progressPct > 0 ? "1px solid var(--foreground)" : "none",
+                          }}
+                        />
+                      </div>
+                    </div>
+                  )}
+
+                  {expiresAt && (
+                    <p className="text-xs" style={{ color: "var(--muted-foreground)" }}>
+                      Доступ до {new Date(expiresAt).toLocaleDateString("ru-RU")}
+                    </p>
+                  )}
                 </div>
               </Link>
             );