Lab assignment management UI and student variant view

- progress-service: POST /api/v1/assign (manual variant), GET /api/v1/assignments?labId=
  (enriched assignments), fixed enrich() to return real variant number/title/statement
- gateway: routes for /api/v1/assign and /api/v1/levels (exact paths)
- web: lab detail page shows students grouped with level and variant selects,
  group filter, distribute/redistribute buttons, source badge (auto/manual)
- web: student dashboard renders variant statement via libs/markdown (spoilers,
  code highlight, sanitized)
- academic-service: unquote YAML front-matter values (variant numbers were quoted)
- academic-service: LabLevelDetail.id for level references

web/src/main/resources/templates/admin/lab.html

@@ -3,13 +3,20 @@
 <head><title th:text="${lab.title} + ' — LMS'">Лабораторная</title></head>
 <body>
 <div id="content">
-    <a th:href="@{/admin/labs}" class="text-sm">← Все лабораторные</a>
-    <div class="mt-4 mb-6 flex flex-wrap items-center justify-between gap-4">
-        <div><h1 class="page-title" th:text="|${lab.number}. ${lab.title}|">ЛР 1</h1><p class="text-sm text-muted">Статус: <span class="badge" th:classappend="${lab.status == 'published'} ? 'badge-ok' : 'badge-warn'" th:text="${lab.status}">—</span></p></div>
-        <form th:action="@{/admin/labs/{id}/distribute(id=${lab.id})}" method="post">
-            <button class="btn btn-primary" type="submit" name="force" value="false">Распределить</button>
-            <button class="btn btn-secondary" type="submit" name="force" value="true">Перераспределить (сбросить ручные)</button>
-        </form>
+    <a th:href="@{/admin/labs}" class="nav-link">← Все лабораторные</a>
+    <div class="flex flex-wrap items-center justify-between gap-4 mt-4 mb-6">
+        <div>
+            <h1 class="page-title" th:text="|${lab.number}. ${lab.title}|">ЛР 1</h1>
+            <p class="text-sm text-muted">Статус: <span class="badge" th:classappend="${lab.status == 'published'} ? 'badge-ok' : 'badge-warn'" th:text="${lab.status}">—</span></p>
+        </div>
+        <div class="flex gap-2">
+            <form th:action="@{/admin/labs/{id}/distribute(id=${lab.id})}" method="post">
+                <button class="btn btn-primary" type="submit" name="force" value="false">Распределить</button>
+            </form>
+            <form th:action="@{/admin/labs/{id}/distribute(id=${lab.id})}" method="post">
+                <button class="btn btn-secondary" type="submit" name="force" value="true">Перераспределить</button>
+            </form>
+        </div>
     </div>
     <div th:if="${notice}" class="alert alert-success" th:text="${notice}"></div>
     <div th:if="${error}" class="alert alert-error" th:text="${error}"></div>
@@ -20,24 +27,73 @@
             <thead><tr><th>Код</th><th>Название</th><th>Вариантов</th></tr></thead>
             <tbody>
             <tr th:each="level : ${lab.levels}">
-                <td th:text="${level.code}">—</td>
+                <td class="font-mono" th:text="${level.code}">—</td>
                 <td th:text="${level.title}">—</td>
                 <td th:text="${#lists.size(level.variants)}">0</td>
             </tr>
+            <tr th:if="${#lists.isEmpty(lab.levels)}"><td colspan="3" class="empty">Уровни не найдены.</td></tr>
             </tbody>
         </table>
     </div>
 
-    <h2 class="section-title">Студенты и варианты</h2>
-    <p class="text-sm text-muted mb-4">Нажмите «Распределить», чтобы закрепить варианты. Можно задать уровень студента.</p>
-    <div class="card card-flush">
-        <table>
-            <thead><tr><th>Студент</th><th>Уровень</th><th>Вариант</th></tr></thead>
-            <tbody id="student-rows">
-            <!-- Filled dynamically after distribution -->
-            </tbody>
-        </table>
+    <div class="flex items-center justify-between gap-4 mb-4">
+        <h2 class="section-title">Студенты и варианты</h2>
+        <label class="text-sm text-muted">Группа:
+            <select id="group-filter" class="input filter-select" onchange="filterGroups(this.value)">
+                <option value="">Все</option>
+                <option th:each="g : ${groups}" th:value="${g.groupName}" th:text="${g.groupName}">—</option>
+            </select>
+        </label>
     </div>
+    <p class="text-sm text-muted mb-4">Уровень по умолчанию — самый простой. Селекты позволяют выдать вариант посложнее или назначить вариант вручную.</p>
+
+    <div class="group-section" th:each="g : ${groups}" th:data-group="${g.groupName}">
+        <h3 class="group-title" th:text="${g.groupName}">Группа</h3>
+        <div class="card card-flush mb-6">
+            <table>
+                <thead><tr><th>Студент</th><th>Логин</th><th>Уровень</th><th>Вариант</th><th>Источник</th></tr></thead>
+                <tbody>
+                <tr th:each="s : ${g.students}">
+                    <td th:text="${s.fullName}">—</td>
+                    <td class="font-mono" th:text="${s.studentNo}">—</td>
+                    <td>
+                        <form class="inline-form" th:action="@{/admin/labs/{labId}/set-level(labId=${lab.id})}" method="post">
+                            <input type="hidden" name="studentId" th:value="${s.studentId}">
+                            <select class="input input-sm" name="labLevelId">
+                                <option th:each="level : ${lab.levels}" th:value="${level.id}" th:text="${level.title}"
+                                        th:selected="${level.id == s.levelId}">—</option>
+                            </select>
+                            <button class="btn btn-secondary btn-sm" type="submit">OK</button>
+                        </form>
+                    </td>
+                    <td>
+                        <form class="inline-form" th:action="@{/admin/labs/{labId}/assign(labId=${lab.id})}" method="post">
+                            <input type="hidden" name="studentId" th:value="${s.studentId}">
+                            <select class="input input-sm" name="variantId">
+                                <optgroup th:each="level : ${lab.levels}" th:label="${level.title}">
+                                    <option th:each="v : ${level.variants}" th:value="${v.id}"
+                                            th:text="|${v.number} — ${v.title}|"
+                                            th:selected="${v.id == s.variantId}">—</option>
+                                </optgroup>
+                            </select>
+                            <button class="btn btn-secondary btn-sm" type="submit">OK</button>
+                        </form>
+                    </td>
+                    <td><span th:if="${s.variantNumber != null}" class="font-mono" th:text="${s.variantNumber}">—</span></td>
+                    <td><span class="badge" th:classappend="${s.source == 'вручную'} ? 'badge-warn' : 'badge-ok'" th:text="${s.source}">—</span></td>
+                </tr>
+                <tr th:if="${#lists.isEmpty(g.students)}"><td colspan="6" class="empty">В группе нет студентов.</td></tr>
+                </tbody>
+            </table>
+        </div>
+    </div>
+    <script>
+        function filterGroups(name) {
+            document.querySelectorAll('.group-section').forEach(function (el) {
+                el.classList.toggle('hidden', !!name && el.getAttribute('data-group') !== name);
+            });
+        }
+    </script>
 </div>
 </body>
 </html>