feat(grpc): add gRPC server infrastructure and schedule sync service

Add gRPC server support with configurable TLS, environment-based settings, and Wire injection. Implement schedule synchronization service with task runner integration for external course data fetching.

- Add gRPC configuration with env var overrides (APP_GRPC_ENABLED, APP_GRPC_PORT, etc.)
- Create gRPC server infrastructure with runner task management
- Implement ScheduleSyncService for course data synchronization
- Add sync endpoint to schedule handler for external system integration
- Update repository with context-aware batch delete operation
- Wire all dependencies including zap logger for structured logging

internal/router/router.go

@@ -170,6 +170,7 @@ func (r *Router) setupRoutes() {
 			{
 				schedule.GET("/courses", r.scheduleHandler.ListCourses)
 				schedule.POST("/courses", r.scheduleHandler.CreateCourse)
+				schedule.POST("/sync", r.scheduleHandler.SyncSchedule) // 同步课表
 				schedule.PUT("/courses/:id", r.scheduleHandler.UpdateCourse)
 				schedule.DELETE("/courses/:id", r.scheduleHandler.DeleteCourse)
 			}