Phase 7: deployment, data import, UI hardening and security fixes

Docker/prod deployment:
- multi-stage Dockerfile (JDK21 build, JRE21 run), docker-compose.prod.yml,
  nginx config for lms.our-place.ru, deploy.sh; DEPLOY/IMPORT guides (UI flow)
- Fix Docker 401: LMS_JWT_JWK_SET_URI for academic/progress; forward-headers

Variant distribution (lab page only):
- round-robin by student level, shared random queue across selected groups,
  least-used variants, manual pins always preserved; occupied/dup labels
- setup page: single form + one «Сохранить всё», batch level/variant for
  selected students (checkboxes)

Grades, defense, materials:
- publication gate + comment lists; defense CSV import (2/3 cols, quotes)
- additional task after defense ("начать заново"); enroll/unenroll students
  from group page; temporary-password lock (no navigation until changed) and
  persistent "Смена пароля"; forced change once
- chapter page /learn/{c}; header: LMS home, Войти, user -> dashboard,
  compact theme toggle; responsive mobile header
- markdown: single newlines are soft breaks; highlight.js with light/dark themes
- lab/content imports ZIP-only (lab.yaml+README+variants/assets,
  chapters tree+assets); duplicate lab numbers rejected; variant ordering
  and date defaults honored

Fixes:
- 500 on student create (@MapsId set before persist); broken dialogs/JS refs in group page

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

@@ -14,7 +14,7 @@
                     <span th:if="${c.variantNumber}" class="badge badge-warn">Вариант <span class="font-mono" th:text="${c.variantNumber}"></span></span>
                     <span th:if="${c.submissionSeq}" class="badge badge-ok">сдано (попытка <span th:text="${c.submissionSeq}"></span>)</span>
                     <span th:unless="${c.submissionSeq}" class="badge badge-warn">не сдано</span>
-                    <span th:if="${c.grade}" class="badge badge-ok">оценка <span th:text="${c.grade}"></span></span>
+                    <span th:if="${c.grade}" class="badge badge-ok">оценка: <span th:text="${c.grade}"></span></span>
                 </div>
                 <p class="text-sm text-muted mt-2" th:if="${c.deadlineMsk}" th:text="|Срок сдачи: ${c.deadlineMsk} МСК|">—</p>
             </div>