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/repository/schedule_repo.go

@@ -1,6 +1,8 @@
 package repository
 
 import (
+	"context"
+
 	"carrot_bbs/internal/model"
 
 	"gorm.io/gorm"
@@ -12,6 +14,7 @@ type ScheduleRepository interface {
 	Create(course *model.ScheduleCourse) error
 	Update(course *model.ScheduleCourse) error
 	DeleteByID(id string) error
+	DeleteByUserID(ctx context.Context, userID string) error
 	ExistsColorByUser(userID, color, excludeID string) (bool, error)
 }
 
@@ -52,6 +55,10 @@ func (r *scheduleRepository) DeleteByID(id string) error {
 	return r.db.Delete(&model.ScheduleCourse{}, "id = ?", id).Error
 }
 
+func (r *scheduleRepository) DeleteByUserID(ctx context.Context, userID string) error {
+	return r.db.WithContext(ctx).Delete(&model.ScheduleCourse{}, "user_id = ?", userID).Error
+}
+
 func (r *scheduleRepository) ExistsColorByUser(userID, color, excludeID string) (bool, error) {
 	var count int64
 	query := r.db.Model(&model.ScheduleCourse{}).