增加pdf上传功能

src/views/KnowledgeContent.vue

@@ -145,7 +145,7 @@
       <div class="dialog-content">
         <!-- 输入方式切换 -->
         <div class="input-mode-switch">
-          <el-radio-group v-model="inputMode" size="large" @change="handleModeChange">
+          <el-radio-group v-model="inputMode" size="large">
             <el-radio-button label="text">📝 文本输入</el-radio-button>
             <el-radio-button label="pdf">📄 PDF上传</el-radio-button>
           </el-radio-group>