feat(runner): implement empty classroom sync functionality

Add support for fetching and synchronizing empty classroom data. This includes new protobuf definitions for task payloads and results, database models, repository, service, and HTTP handlers.

- Add `TASK_TYPE_GET_EMPTY_CLASSROOM` to `TaskType` enum
- Implement `EmptyClassroom` model and auto-migration
- Add `EmptyClassroomHandler` with `GET` and `POST /sync` routes
- Implement `EmptyClassroomSyncService` and `EmptyClassroomRepository`
- Update dependency injection with wire sets

internal/handler/empty_classroom_handler.go

@@ -0,0 +1,87 @@
+package handler
+
+import (
+	"github.com/gin-gonic/gin"
+
+	"with_you/internal/pkg/response"
+	"with_you/internal/repository"
+	"with_you/internal/service"
+)
+
+type EmptyClassroomHandler struct {
+	classroomSyncService service.EmptyClassroomSyncService
+	classroomRepo        repository.EmptyClassroomRepository
+}
+
+func NewEmptyClassroomHandler(
+	classroomSyncService service.EmptyClassroomSyncService,
+	classroomRepo repository.EmptyClassroomRepository,
+) *EmptyClassroomHandler {
+	return &EmptyClassroomHandler{
+		classroomSyncService: classroomSyncService,
+		classroomRepo:        classroomRepo,
+	}
+}
+
+type syncEmptyClassroomsRequest struct {
+	Username   string `json:"username" binding:"required"`
+	Password   string `json:"password" binding:"required"`
+	Semester   string `json:"semester"`
+	WeekStart  string `json:"week_start"`
+	WeekEnd    string `json:"week_end"`
+	CampusCode string `json:"campus_code"`
+}
+
+func (h *EmptyClassroomHandler) SyncEmptyClassrooms(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		response.Unauthorized(c, "")
+		return
+	}
+
+	var req syncEmptyClassroomsRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "invalid request: "+err.Error())
+		return
+	}
+
+	result, err := h.classroomSyncService.SyncUserEmptyClassrooms(c.Request.Context(), userID, &service.SyncEmptyClassroomsRequest{
+		Username:   req.Username,
+		Password:   req.Password,
+		Semester:   req.Semester,
+		WeekStart:  req.WeekStart,
+		WeekEnd:    req.WeekEnd,
+		CampusCode: req.CampusCode,
+	})
+	if err != nil {
+		response.HandleError(c, err, "failed to sync empty classrooms")
+		return
+	}
+
+	if !result.Success {
+		response.Success(c, result)
+		return
+	}
+	response.SuccessWithMessage(c, result.Message, result)
+}
+
+func (h *EmptyClassroomHandler) ListEmptyClassrooms(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		response.Unauthorized(c, "")
+		return
+	}
+	semester := c.Query("semester")
+	if semester == "" {
+		response.BadRequest(c, "semester is required")
+		return
+	}
+
+	classrooms, err := h.classroomRepo.ListByUserAndSemester(userID, semester)
+	if err != nil {
+		response.HandleError(c, err, "failed to list empty classrooms")
+		return
+	}
+
+	response.Success(c, gin.H{"classrooms": classrooms})
+}