UI rework: modal dialogs, inline lab editing, manual creation, content management

- Dashboard: real stats (groups, students, labs, average grade), labs/groups
  summary lists, no placeholder tile
- Lab page: view + edit combined — metadata form in modal, condition rendered
  as markdown, per-level variant tables with add/edit/delete dialogs,
  level rename/delete, student level/variant selectors with group filter
- Labs list: create-lab dialog with manual level entry (code; title lines)
- Groups: create-group dialog, add-student dialog (auto password, toast card)
- Content: public /learn reader is the single place; admin buttons (new
  article with chapter/section create-or-select, rename/delete chapters and
  sections, move articles between sections, import zip) appear for admins;
  removed separate 'Контент' admin section
- Buttons use btn classes instead of nav-link
- Favicon: generated SVG book icon
- Security: CSRF synchronizer token interceptor (replaced spring-security in
  web which broke logback under nested jars), session regenerated on login,
  hardened session cookie, gateway actuator limited to health,info
- Jackson 3: nullable-safe request DTOs for labs (FAIL_ON_NULL_FOR_PRIMITIVES)
- academic: POST /labs (manual create with levels), level add/rename/delete,
  content chapters/sections CRUD, article create/move/delete endpoints

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

@@ -3,18 +3,14 @@
 <head><title>Лабораторные — LMS</title></head>
 <body>
 <div id="content">
-    <h1 class="page-title">Лабораторные</h1>
+    <div class="flex items-center justify-between gap-4 mb-6">
+        <h1 class="page-title">Лабораторные</h1>
+        <button class="btn btn-primary" type="button" onclick="openModal('modal-create-lab')">+ Создать</button>
+    </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>
-    <div class="grid grid-2">
-        <form class="card form-card form-stack" th:action="@{/admin/labs/import}" method="post" enctype="multipart/form-data">
-            <h2 class="section-title">Импорт лабораторной</h2>
-            <p class="text-sm text-muted">Принимаются .zip (lab.yaml + README.md + variants/*.md) или .json.</p>
-            <div><label class="label" for="labFile">Файл</label><input class="input" id="labFile" name="file" type="file" accept=".zip,.json" required></div>
-            <button class="btn btn-primary" type="submit">Импортировать</button>
-        </form>
-    </div>
-    <div class="card card-flush mt-8">
+
+    <div class="card card-flush">
         <table>
             <thead><tr><th>№</th><th>Название</th><th>Вариантов</th><th>Статус</th><th></th></tr></thead>
             <tbody>
@@ -23,12 +19,49 @@
                 <td><a th:href="@{/admin/labs/{id}(id=${lab.id})}" th:text="${lab.title}">—</a></td>
                 <td th:text="${lab.variantCount}">0</td>
                 <td><span class="badge" th:classappend="${lab.status == 'published'} ? 'badge-ok' : 'badge-warn'" th:text="${lab.status}">—</span></td>
-                <td class="text-center"><form th:action="@{/admin/labs/{id}/delete(id=${lab.id})}" method="post"><button class="nav-link text-sm" type="submit">Удалить</button></form></td>
+                <td class="text-center"><form th:action="@{/admin/labs/{id}/delete(id=${lab.id})}" method="post"><input type="hidden" name="_csrf" th:value="${csrfToken}"><button class="btn btn-danger btn-sm" type="submit">Удалить</button></form></td>
             </tr>
             <tr th:if="${#lists.isEmpty(labs)}"><td colspan="5" class="empty">Лабораторных пока нет.</td></tr>
             </tbody>
         </table>
     </div>
 </div>
+
+<dialog id="modal-create-lab" class="modal">
+    <div class="modal-header">
+        <h2 class="modal-title">Новая лабораторная</h2>
+        <button class="modal-close" type="button" onclick="closeModal('modal-create-lab')">✕</button>
+    </div>
+    <div class="modal-body">
+        <form class="form-stack" th:action="@{/admin/labs/create}" method="post">
+            <div class="grid grid-2">
+                <div><label class="label" for="labNumber">Номер</label>
+                    <input class="input" id="labNumber" name="number" type="number" min="1" required></div>
+                <div><label class="label" for="labPoints">Максимум баллов</label>
+                    <input class="input" id="labPoints" name="pointsMax" type="number" step="0.1" min="0" value="5" required></div>
+            </div>
+            <div><label class="label" for="labTitle">Название</label>
+                <input class="input" id="labTitle" name="title" required></div>
+            <div class="grid grid-2">
+                <div><label class="label" for="labDeadline">Срок сдачи</label>
+                    <input class="input" id="labDeadline" name="deadlineAt" type="datetime-local"></div>
+                <div><label class="label" for="labDefense">Дата защиты</label>
+                    <input class="input" id="labDefense" name="defenseAt" type="datetime-local"></div>
+            </div>
+            <div><label class="label" for="labStatus">Статус</label>
+                <select class="input" id="labStatus" name="status">
+                    <option value="draft">draft</option>
+                    <option value="published">published</option>
+                </select></div>
+            <div><label class="label" for="labLevels">Уровни (по одному на строку: код; название)</label>
+                <textarea class="input" id="labLevels" name="levels" rows="4" placeholder="basic; Основная группа&#10;advanced; Повышенная сложность"></textarea>
+                <p class="hint">Если оставить пустым, будет создан уровень «Основная группа». Варианты добавите на странице лабы.</p></div>
+            <div><label class="label" for="labDesc">Условие (markdown, можно позже)</label>
+                <textarea class="input" id="labDesc" name="descriptionMd" rows="6"></textarea></div>
+            <button class="btn btn-primary" type="submit">Создать</button>
+        <input type="hidden" name="_csrf" th:value="${csrfToken}">
+        </form>
+    </div>
+</dialog>
 </body>
 </html>