fix: add missing @RequirePermission decorators
Adds @RequirePermission to 19 TS GraphQL resolvers across 5
subgraphs (iam, config-service, core-edu, content, msg) per
audit report §6.1. Maps: iam user/role -> IAM_USER_READ;
config-service 5 queries -> CONFIG_USER; core-edu classInfo ->
CLASS_READ, exam -> EXAM_READ, grade -> GRADE_READ, homework
-> HOMEWORK_READ, datascope visibleGrades/visibleExams ->
GRADE_READ/EXAM_READ; content chapter/knowledgePoint/question/
textbook -> CONTENT_*_READ; msg notifications ->
MSG_NOTIFICATION_READ, template -> MSG_NOTIFICATION_MANAGE.
Federation resolveReference left unguarded. Python subgraphs
(data-ana, ai) deferred to follow-up infrastructure work.
1b5781bf42