feat: 行程卡片间显示交通路线描述和时间

- get_travel_time 解析 Amap segments 提取线路名和站数
- PlanItem 新增 transitToNext / transitDescription 字段
- finalize_plan schema 加入 transit_to_next_description
- 修复 Turbopack 中文引号解析报错
- UI 连接器改为两行布局，路线描述与时长分行显示

src/components/BlindboxPlan.tsx

@@ -469,6 +469,20 @@ export default function BlindboxPlan({
                         setDraft({ ...item });
                       }}
                     />
+                    {/* Transit connector to next activity */}
+                    {item.transitToNext != null && i < currentDay.items.length - 1 && (
+                      <div className="flex items-start gap-1.5 py-2 pl-1">
+                        <Navigation size={9} className="mt-0.5 shrink-0 text-purple-400/40" />
+                        <div className="flex flex-col gap-0.5">
+                          {item.transitDescription && (
+                            <span className="text-[10px] leading-snug text-dim">
+                              {item.transitDescription}
+                            </span>
+                          )}
+                          <span className="text-[10px] text-dim/70">约 {item.transitToNext} 分钟</span>
+                        </div>
+                      </div>
+                    )}
                   </motion.div>
                 ))}
               </SortableContext>