新增每门课程的“优先上课日 / 偏好节次范围”，与硬性可排范围分离。

遗传算法在满足冲突、容量、场地等硬约束后，优先满足课程偏好；偏好无法满足时仍会安排可行课次。
管理员可通过“课程偏好权重”控制偏好的影响程度。
修复遗传适应度：教室容量冗余、同一任务分散、日负载和实验场地偏好现在都会实际参与种群评分

web/src/views/SchedulesView.vue

@@ -43,6 +43,7 @@ const optimizationSettings = reactive({
   earlyPeriodPenalty: 30,
   latePeriodPenalty: 30,
   roomCapacityWasteWeight: 1,
+  coursePreferenceWeight: 180,
 })
 const optimizationSaving = ref(false)
 const constraintFilters = reactive({
@@ -387,6 +388,9 @@ function openConstraint(item: any) {
       : [1, 2, 3, 4, 5],
     earliestPeriod: item.earliestPeriod,
     latestPeriod: item.latestPeriod,
+    preferredDayOfWeeks: [...(item.preferredDayOfWeeks ?? [])],
+    preferredEarliestPeriod: item.preferredEarliestPeriod,
+    preferredLatestPeriod: item.preferredLatestPeriod,
   })
   constraintDialog.value = true
 }
@@ -407,6 +411,9 @@ async function saveConstraint() {
       allowedDayOfWeeks: constraintForm.allowedDayOfWeeks ?? [],
       earliestPeriod: constraintForm.earliestPeriod || null,
       latestPeriod: constraintForm.latestPeriod || null,
+      preferredDayOfWeeks: constraintForm.preferredDayOfWeeks ?? [],
+      preferredEarliestPeriod: constraintForm.preferredEarliestPeriod || null,
+      preferredLatestPeriod: constraintForm.preferredLatestPeriod || null,
     }
     await http.put(`/schedules/constraints/${constraintForm.teachingTaskId}`, payload)
     constraintDialog.value = false
@@ -1266,7 +1273,7 @@ onBeforeUnmount(() => {
             show-icon
           />
           <el-form label-position="top" class="optimization-form">
-            <div class="form-grid">
+         <div class="form-grid">
               <el-form-item label="教师同日课次惩罚">
                 <el-input-number v-model="optimizationSettings.teacherSameDayWeight" :min="0" :max="10000" />
                 <small class="field-hint">优先将同一教师的课程分散到不同日期。</small>
@@ -1295,6 +1302,10 @@ onBeforeUnmount(() => {
                 <el-input-number v-model="optimizationSettings.roomCapacityWasteWeight" :min="0" :max="10000" />
                 <small class="field-hint">优先使用容量更贴合教学班人数的可用教室。</small>
               </el-form-item>
+              <el-form-item label="课程偏好权重">
+                <el-input-number v-model="optimizationSettings.coursePreferenceWeight" :min="0" :max="10000" />
+                <small class="field-hint">课程设置了偏好日期或节次时，优先满足该偏好。</small>
+              </el-form-item>
             </div>
           </el-form>
         </el-tab-pane>
@@ -1456,6 +1467,25 @@ onBeforeUnmount(() => {
             </el-select>
           </el-form-item>
          </div>
+         <el-divider content-position="left">排课偏好（可不填）</el-divider>
+         <el-form-item label="优先上课日">
+           <el-checkbox-group v-model="constraintForm.preferredDayOfWeeks">
+             <el-checkbox v-for="day in weekdays" :key="day.value" :value="day.value">{{ day.label }}</el-checkbox>
+           </el-checkbox-group>
+           <small class="field-hint">不是硬限制；无冲突的前提下，遗传算法会优先选择这些日期。</small>
+         </el-form-item>
+         <div class="form-grid">
+           <el-form-item label="偏好最早开始节次">
+             <el-select v-model="constraintForm.preferredEarliestPeriod" clearable>
+               <el-option v-for="period in periods" :key="period" :label="`第 ${period} 节 · ${timeLabel(period)}`" :value="period" />
+             </el-select>
+           </el-form-item>
+           <el-form-item label="偏好最晚结束节次">
+             <el-select v-model="constraintForm.preferredLatestPeriod" clearable>
+               <el-option v-for="period in periods" :key="period" :label="`第 ${period} 节 · ${timeLabel(period)}`" :value="period" />
+             </el-select>
+           </el-form-item>
+         </div>
          </template>
        </el-form>
       <template #footer>