Image preview top controls are outside the visible viewport on Android Chrome

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Describe the bug

When opening an attached image in the image preview on Android Chrome, the controls at the top of the viewer can be positioned outside the visible viewport.

In particular, the Close and Info buttons move above the visible screen area and become inaccessible.

The issue is reproducible both on the stable v0.31.0 release and on the current Memos demo build.

Expected behavior

The image preview toolbar, including the Close and Info buttons, should always remain inside the visible viewport on mobile devices.

Steps to reproduce

1. Open Memos in Chrome on an Android phone.
2. Open a memo containing an image attachment.
3. Tap the image to open the full-screen image preview.
4. Observe the controls at the top of the preview.
5. The Close and Info buttons are positioned partly or completely outside the visible screen area.

Memos version

v0.31.0

Additional context

Also reproduced on the current demo build:

v0.31.0 commit cb42e326ba9cc266a6a9570c53e0fe04c62793f4

Browser: Google Chrome 153.0.8010.52 Platform: Android Browser mode: regular Chrome browser, not PWA

The issue is reproducible both on my self-hosted v0.31.0 instance and on the official Memos demo.

Demo commit: https://github.com/usememos/memos/commit/cb42e326ba9cc266a6a9570c53e0fe04c62793f4

Screenshot attached.