fix(ai-content): 添加大纲和角色生成的加载状态

- 步骤1按钮点击后显示"生成大纲中..."
- 步骤2按钮点击后显示"生成角色中..."
- 添加uni.showLoading加载提示

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

my-uniapp-vue3/src/pages/ai-content/index.vue

@@ -106,7 +106,10 @@
           </view>
         </view>
 
-        <button class="next-btn" @click="goToStep2">下一步：生成大纲 →</button>
+        <button class="next-btn" :disabled="generatingOutline" @click="goToStep2">
+          <text v-if="generatingOutline">生成大纲中...</text>
+          <text v-else>下一步：生成大纲 →</text>
+        </button>
       </view>
 
       <!-- 步骤2：大纲预览 -->
@@ -141,7 +144,10 @@
 
         <view class="btn-row">
           <button class="back-btn" @click="currentStep = 0">← 上一步</button>
-          <button class="next-btn" @click="goToStep3">下一步：生成内容 →</button>
+          <button class="next-btn" :disabled="generating" @click="goToStep3">
+          <text v-if="generatingCharacters">生成角色中...</text>
+          <text v-else>下一步：生成内容 →</text>
+        </button>
         </view>
       </view>
 
@@ -330,6 +336,7 @@ const outline = ref<{ title: string; description: string; wordCount: number }[]>
 
 // 角色
 const characters = ref<any[]>([]);
+const generatingCharacters = ref(false);
 
 // 内容生成
 const generating = ref(false);
@@ -369,12 +376,18 @@ async function goToStep2() {
     uni.showToast({ title: '请输入创作主题', icon: 'none' });
     return;
   }
+  uni.showLoading({ title: '正在生成大纲...' });
   await generateOutline();
-  currentStep.value = 1;
+  uni.hideLoading();
+  if (outline.value.length > 0) {
+    currentStep.value = 1;
+  }
 }
 
 async function goToStep3() {
+  uni.showLoading({ title: '正在生成角色...' });
   await generateCharacters();
+  uni.hideLoading();
   currentStep.value = 2;
 }
 
@@ -399,6 +412,7 @@ async function regenerateOutline() {
 }
 
 async function generateCharacters() {
+  generatingCharacters.value = true;
   try {
     const result = await post<any>('/ai-content/characters/generate', {
       type: selectedType.value,
@@ -410,6 +424,8 @@ async function generateCharacters() {
       { id: 'char-1', name: '张三', age: 30, gender: '男', personality: '正直勇敢', role: '主角' },
       { id: 'char-2', name: '李四', age: 28, gender: '女', personality: '聪明机智', role: '女主' },
     ];
+  } finally {
+    generatingCharacters.value = false;
   }
 }