feat: 新增过渡页面路由、上传组件及完善跳转逻辑

- 为conquerPackage模块添加过渡页面路由并实现页面跳转逻辑
- 新增通用多图上传组件Upload，支持多种模式与图片操作功能
- 新增任务相关的API及Model基础文件
- 注释课前课中页面的测试试题内容

lib/features/conquerPackage/beforeDuringClass/index.dart

@@ -2,6 +2,7 @@ import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter_screenutil/flutter_screenutil.dart';
+import 'package:go_router/go_router.dart';
 import 'package:new_learn/core/api/conquerPackage/beforeDuringClass/api.dart';
 import 'package:new_learn/core/api/conquerPackage/beforeDuringClass/model.dart';
 import 'package:new_learn/core/api/public_upload/model.dart';
@@ -176,6 +177,13 @@ class _BeforeDuringClassPageState extends State<BeforeDuringClassPage>
             .getListByRecordHandout(_recordId);
       }
       _pageList = List<HandoutItem>.from(resp.items);
+
+      // _pageList = List<HandoutItem>.from(resp.items).map((item) {
+      //   return item.copyWith(
+      //     content: item.content +
+      //         '<div class="hxdb-stem" name="hxdbStem"><div class="hxdb-stem-content" name="hxdbStem-content" data-hxdb-type="stem"><p>某兴趣小组利用 Pt1000 铂电阻测量温度。实验中没有电压表，现将电流表 <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/878136bf67384b3ab5998cc6fc15bc32_0_398c9b77.svg" width="25" height="17" style="width: 25px; height: 17px; vertical-align: middle;"> 与已知电阻 <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/5a406b64eafd47f3a8686bba4741c29a_1_b71473bc.svg" width="26" height="17" style="width: 26px; height: 17px; vertical-align: middle;"> 串联组成一条支路，将电流表 <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/167759d79f984e45a0d48c31a3c6566e_2_fb3fd646.svg" width="26" height="17" style="width: 26px; height: 17px; vertical-align: middle;"> 与待测铂电阻 <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/f769c572150d4ce782daa8935a9ceb83_3_b1a4eeff.svg" width="23" height="16" style="width: 23px; height: 16px; vertical-align: middle;"> 串联组成另一条支路，两支路并联。忽略两电流表内阻，<img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/d37447ecfe6440d1bd97e900cacf3b64_4_398c9b77.svg" width="25" height="17" style="width: 25px; height: 17px; vertical-align: middle;">、<img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/8a5d7731a3b744d193a514eeb253ca92_5_fb3fd646.svg" width="26" height="17" style="width: 26px; height: 17px; vertical-align: middle;"> 的示数分别为 <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/9265c18c28934f61bc64bef449f1e641_6_6c3f86e2.svg" width="19" height="16" style="width: 19px; height: 16px; vertical-align: middle;">、<img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/b0fdd5ecc5a0477eb7a245d2c0fcf041_7_93189365.svg" width="20" height="17" style="width: 20px; height: 17px; vertical-align: middle;">。铂电阻阻值 <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/340415fadcf24d87a7ed79eb81a64c30_8_b1a4eeff.svg" width="23" height="16" style="width: 23px; height: 16px; vertical-align: middle;"> 的表达式为</p><p><br><img src="https://hx.cnzhyx.cn/K12/Question/png/2026-08-24/85cb7f0925a841c6b894ce351678be4f.png" class="preview-content" style="max-width:100%;"><br></p></div><table class="hxdb-option-table" name="hxdbOptionTable" style="width: 100%; table-layout: fixed; border-collapse: collapse;"><tbody><tr class="hxdb-option-table-tr firstRow" name="hxdbOptionTableTr"><td class="hxdb-option-table-td" name="hxdbOptionTableTd" valign="top" style="word-break: break-all;"><span class="hxdb-option-label">A.</span>  <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/3094744dbf1644bb80aceae639e61c6a_9_7f8b9fc5.svg" width="92" height="40" style="width: 92px; height: 40px; vertical-align: middle;"></td></tr><tr class="hxdb-option-table-tr firstRow" name="hxdbOptionTableTr"><td class="hxdb-option-table-td" name="hxdbOptionTableTd" valign="top" style="word-break: break-all;"><span class="hxdb-option-label">B.</span>  <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/96acf8a47eda4cdf81ef01707a28abff_10_fa759021.svg" width="92" height="40" style="width: 92px; height: 40px; vertical-align: middle;"></td></tr><tr class="hxdb-option-table-tr firstRow" name="hxdbOptionTableTr"><td class="hxdb-option-table-td" name="hxdbOptionTableTd" valign="top" style="word-break: break-all;"><span class="hxdb-option-label">C.</span>  <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/aecc386b27d341e393bbc45ac86e9e20_11_7cd89d59.svg" width="144" height="42" style="width: 144px; height: 42px; vertical-align: middle;"></td></tr><tr class="hxdb-option-table-tr firstRow" name="hxdbOptionTableTr"><td class="hxdb-option-table-td" name="hxdbOptionTableTd" valign="top" style="word-break: break-all;"><span class="hxdb-option-label">D.</span>  <img src="https://hx.cnzhyx.cn/K12LatexToSvg/ProductionV2/LatexSvg/2026-08-27/6c8a4a6004f04529b9d6b48b4d7560c3_12_1f4bbe90.svg" width="144" height="42" style="width: 144px; height: 42px; vertical-align: middle;"></td></tr></tbody></table></div>',
+      //   );
+      // }).toList();
       // _pageList = List<HandoutItem>.from(resp.items).map((item) {
       //   return item.copyWith(
       //     isUploadNotes: true,
@@ -480,8 +488,17 @@ class _BeforeDuringClassPageState extends State<BeforeDuringClassPage>
   }
 
   void _goTransitionPage() {
-    // TODO: 跳转到 transition 页，等路由配置好后替换
-    Navigator.of(context).pop();
+    // 判断下一个状态：课前(1)→课中(2)→课后(3)
+    // 此处简化：完成学习后默认进入课后练习过渡页（status=3）
+    context.push(
+      '/conquerPackage/transitionPage',
+      extra: {
+        'courseId': _courseId,
+        'packId': _packId,
+        'recordId': _recordId,
+        'status': '3',
+      },
+    );
   }
 
   // ===================== 笔记变化 =====================