feat(modules): module topics for student form, admin CRUD with pagination

- db: modules table (name, lessons_count) + entries.module_id (ON DELETE SET NULL), migration + idempotent startup ensure
- api: GET /api/modules (public, search + limit/offset, entries_count), POST/PUT/DELETE (admin, audit-logged)
- entries: accept/validate module_id on create/update, return module_name, module_id filter
- backup/restore: include modules and entries.module_id
- student form: required module select, hidden while no modules exist
- admin: modules.html + js/modules.js list with pagination, search, create/edit/delete modal
- journal: module filter, module select in edit modal, module badge, CSV column

public/journal.html

@@ -43,6 +43,7 @@
       <div><label>Поиск</label><input type="text" id="searchInput" class="search-input" placeholder="Имя или описание"></div>
       <div><label>Студент</label><input type="text" id="studentFilter" list="studentFilterList" placeholder="Все / введите имя..."><datalist id="studentFilterList"></datalist></div>
       <div><label>Группа</label><select id="groupFilter"><option value="">Все группы</option></select></div>
+      <div><label>Модуль</label><select id="moduleFilter"><option value="">Все модули</option></select></div>
       <div><label>С</label><input type="date" id="dateFrom"></div>
       <div><label>По</label><input type="date" id="dateTo"></div>
       <div><label>&nbsp;</label><button type="button" id="exportCsvBtn" style="background:var(--card);border:1px solid var(--border);color:var(--text);border-radius:8px;padding:8px 16px;font-size:.85rem;cursor:pointer;white-space:nowrap">Экспорт CSV</button></div>
@@ -76,6 +77,10 @@
         <label>Группа <span style="color:#ef4444">*</span></label>
         <select id="editGroup" class="settings-input" required></select>
       </div>
+      <div class="settings-field">
+        <label>Тема модуля</label>
+        <select id="editModule" class="settings-input"></select>
+      </div>
       <div class="settings-field full">
         <label>Что делала(а) <span style="color:#ef4444">*</span>
           <button type="button" id="aiCorrectBtn" class="ai-btn" title="Исправить ошибки ИИ">✨</button>