feat: 移除项目编码手动输入

- 项目编码由后端自动生成
- 移除表单中的项目编码输入框和验证规则

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

src/views/martial/project/index.vue

@@ -247,17 +247,6 @@
             </el-form-item>
           </el-col>
         </el-row>
-        <el-row :gutter="20">
-          <el-col :span="12">
-            <el-form-item label="项目编码" prop="projectCode">
-              <el-input
-                v-model="form.projectCode"
-                placeholder="请输入项目编码"
-                maxlength="50"
-              />
-            </el-form-item>
-          </el-col>
-        </el-row>
         <el-row :gutter="20">
           <el-col :span="12">
             <el-form-item label="项目名称" prop="projectName">
@@ -523,10 +512,6 @@ const rules = {
   competitionId: [
     { required: true, message: '请选择所属赛事', trigger: 'change' }
   ],
-  projectCode: [
-    { required: true, message: '请输入项目编码', trigger: 'blur' },
-    { min: 2, max: 50, message: '长度在 2 到 50 个字符', trigger: 'blur' }
-  ],
   projectName: [
     { required: true, message: '请输入项目名称', trigger: 'blur' },
     { min: 2, max: 100, message: '长度在 2 到 100 个字符', trigger: 'blur' }