feat(api): implement exam and grade synchronization modules

Add new functionality for managing and synchronizing academic grades and exam schedules. This includes new models, repositories, services, and HTTP handlers, along with updated gRPC definitions and dependency injection configuration.

Additionally, improve the reliability of unread message count tracking by implementing an atomic Lua script for Redis operations in the conversation cache.

internal/router/router.go

@@ -26,6 +26,8 @@ type RouterDeps struct {
 	VoteHandler              *handler.VoteHandler
 	ChannelHandler           *handler.ChannelHandler
 	ScheduleHandler          *handler.ScheduleHandler
+	GradeHandler             *handler.GradeHandler
+	ExamHandler              *handler.ExamHandler
 	RoleHandler              *handler.RoleHandler
 	AdminUserHandler         *handler.AdminUserHandler
 	AdminPostHandler         *handler.AdminPostHandler
@@ -67,6 +69,8 @@ type Router struct {
 	voteHandler              *handler.VoteHandler
 	channelHandler           *handler.ChannelHandler
 	scheduleHandler          *handler.ScheduleHandler
+	gradeHandler             *handler.GradeHandler
+	examHandler              *handler.ExamHandler
 	roleHandler              *handler.RoleHandler
 	adminUserHandler         *handler.AdminUserHandler
 	adminPostHandler         *handler.AdminPostHandler
@@ -111,6 +115,8 @@ func New(deps RouterDeps) *Router {
 		voteHandler:              deps.VoteHandler,
 		channelHandler:           deps.ChannelHandler,
 		scheduleHandler:          deps.ScheduleHandler,
+		gradeHandler:             deps.GradeHandler,
+		examHandler:              deps.ExamHandler,
 		roleHandler:              deps.RoleHandler,
 		adminUserHandler:         deps.AdminUserHandler,
 		adminPostHandler:         deps.AdminPostHandler,
@@ -346,6 +352,26 @@ func (r *Router) setupRoutes() {
 			}
 		}
 
+		// 成绩路由
+		if r.gradeHandler != nil {
+			grades := v1.Group("/grades")
+			grades.Use(authMiddleware)
+			{
+				grades.GET("", r.gradeHandler.ListGrades)
+				grades.POST("/sync", r.gradeHandler.SyncGrades)
+			}
+		}
+
+		// 考试安排路由
+		if r.examHandler != nil {
+			exams := v1.Group("/exams")
+			exams.Use(authMiddleware)
+			{
+				exams.GET("", r.examHandler.ListExams)
+				exams.POST("/sync", r.examHandler.SyncExams)
+			}
+		}
+
 		// 学习资料路由（公开）
 		if r.materialHandler != nil {
 			materials := v1.Group("/materials")