feat(backend): 调整课程日期为周日并优化计划提交时间窗口

- 将上课日从周六调整为周日，新增 CLASS_WEEKDAY 常量
- 更新 get_class_date 和 get_sunday_of_week 函数以支持周日计算
- 修改 generate_week_list 函数生成周日日期而非周六日期
- 重构月计划和年计划的时间窗口逻辑，增加提前提交功能
- 新增 monthly_window 和 yearly_window 函数定义准确的提交窗口期
- 调整默认周期选择逻辑，支持跨月年的时间窗口
- 添加 period_labels 字段提供前端周期标签显示
- 移除旧的 _validate_current_period 函数
- 完善计划提交验证逻辑，支持多种时间周期类型

chore(miniapp): 更新小程序项目配置

- 补充 project.config.json 中的设置选项
- 调整 project.private.config.json 配置结构
- 移除冗余的页面调试条件配置
- 更新编辑器和编译相关配置项

project.private.config.json

@@ -1,47 +1,22 @@
 {
-  "condition": {
-    "miniprogram": {
-      "list": [
-        {
-          "name": "pages/webview/webview",
-          "pathName": "pages/webview/webview",
-          "query": "",
-          "scene": null,
-          "launchMode": "default"
-        },
-        {
-          "name": "pages/profile/profile",
-          "pathName": "pages/profile/profile",
-          "query": "",
-          "launchMode": "default",
-          "scene": null
-        },
-        {
-          "name": "pages/plan/plan",
-          "pathName": "pages/plan/plan",
-          "query": "",
-          "launchMode": "default",
-          "scene": null
-        },
-        {
-          "name": "pages/checkin/checkin",
-          "pathName": "pages/checkin/checkin",
-          "query": "",
-          "launchMode": "default",
-          "scene": null
-        },
-        {
-          "name": "pages/home/home",
-          "pathName": "pages/home/home",
-          "query": "",
-          "launchMode": "default",
-          "scene": null
-        }
-      ]
-    }
-  },
+  "condition": {},
   "setting": {
-    "urlCheck": false
+    "urlCheck": false,
+    "coverView": false,
+    "lazyloadPlaceholderEnable": false,
+    "skylineRenderEnable": false,
+    "preloadBackgroundData": false,
+    "autoAudits": false,
+    "useApiHook": true,
+    "showShadowRootInWxmlPanel": false,
+    "useStaticServer": false,
+    "useLanDebug": false,
+    "showES6CompileOption": false,
+    "compileHotReLoad": true,
+    "checkInvalidKey": true,
+    "ignoreDevUnusedFiles": true,
+    "bigPackageSizeSupport": false
   },
-  "libVersion": "3.16.2"
+  "libVersion": "3.16.2",
+  "projectname": "mingyuan-clock"
 }