refactor: 周期账单 Numpad 改为弹窗内嵌，移除 fixed 定位

client/src/pages/recurring/index.vue

@@ -134,6 +134,11 @@
               </view>
             </picker>
           </view>
+
+          <!-- 数字键盘 -->
+          <view class="form-numpad-wrap">
+            <Numpad v-model="amountStr" />
+          </view>
         </scroll-view>
         <view class="modal-footer" @tap="handleSubmit">
           <text class="submit-text">{{ editingId ? '保存修改' : '添加' }}</text>
@@ -141,10 +146,6 @@
       </view>
     </view>
 
-    <!-- Numpad 放在弹窗内，避免被 modal-mask 遮挡 -->
-    <view class="form-numpad" v-if="showModal">
-      <Numpad v-model="amountStr" />
-    </view>
   </view>
 </template>
 
@@ -500,10 +501,11 @@ function goBack() { uni.navigateBack() }
   &:active { opacity: 0.8; }
 }
 
-/* Numpad 位于弹窗上方 */
-.form-numpad {
-  position: fixed; bottom: 0; left: 0; right: 0; z-index: 250;
-  background: $surface;
-  padding-bottom: env(safe-area-inset-bottom);
+/* Numpad 内嵌在表单中 */
+.form-numpad-wrap {
+  margin-top: $space-sm;
+  background: $bg;
+  border-radius: $radius-lg;
+  overflow: hidden;
 }
 </style>