fix: center input modal to prevent keyboard covering confirm button

Bottom sheet modal gets obscured by virtual keyboard on H5.
Switch to centered dialog + adjust-position=false to keep buttons visible.

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

app/src/pages/progress/progress.vue

@@ -104,9 +104,9 @@ function saveSnapshot() {
       <text class="text-white text-2xl leading-none">+</text>
     </view>
 
-    <!-- 录入弹窗 -->
-    <view v-if="showForm" class="fixed inset-0 bg-black/40 flex items-end" @tap.self="showForm = false">
-      <view class="w-full rounded-t-3xl bg-white p-6">
+    <!-- 录入弹窗（居中，避免键盘遮挡按钮） -->
+    <view v-if="showForm" class="fixed inset-0 bg-black/40 flex items-center px-6" @tap.self="showForm = false">
+      <view class="w-full rounded-2xl bg-white p-6">
         <view class="mb-4 text-lg font-medium text-gray-800">
           录入当前净资产
         </view>
@@ -115,6 +115,8 @@ function saveSnapshot() {
           type="digit"
           placeholder="请输入金额（元）"
           class="w-full rounded-xl border border-gray-200 px-4 py-3 text-base"
+          :adjust-position="false"
+          focus
         />
         <view class="mt-4 flex gap-3">
           <view