Mobile cannot synchronize after resolving multiple project files on server (project had multiple .qgs/.qgz)

Description

When a project initially contains multiple project files (.qgs/.qgz), it cannot be opened on mobile (expected). After deleting one of the project files in Mergin Maps Web so that exactly one project file remains, the project should synchronize on mobile and become openable. Instead, synchronization fails on iOS, Android, and Windows app version 2025.7.0.

Environment
Staging

Application (+ app version, build, operating system)

• Mergin Maps iOS app: 2025.7.0
• iOS version: iOS 26.0
• Mergin Maps Android app: 2025.7.0
• Android: 15
• Mergin Maps Windows app: 2025.7.0
• Windows: Windows 11

Steps to reproduce

1. Prepare a project that contains more than one project file (e.g., project.qgz and project_alt.qgz).
2. Download this project to the Mergin Maps mobile app (iOS, Android, or Windows).
   • Opening the project is blocked with a “multiple project files” message (expected).
3. In Mergin Maps Web, delete one of the project files so the project has exactly one .qgs or .qgz file remaining.
4. In the mobile app, attempt to synchronize (pull the latest from server).

Actual results

• Synchronization does not proceed. The project remains in a non-openable/invalid state on the device even though the server project now contains a single project file.
• If any error banner/dialog appears, the sync is still unsuccessful. In some runs there may be no actionable prompt to complete the sync.
• Workaround: If the local project is removed from the device and then downloaded again after removing the additional project file on Mergin Maps Web, the project can be opened.

Expected results

• After the extra project file is removed on the server, the mobile app should synchronize successfully.
• The project should become openable on mobile, and any “multiple project files” warning should clear automatically after a successful sync.
• If other pending updates exist, they should be visible and not obscured by any outdated warning banners.

Screenshots or logs

Conclusion
Created by GitHub Copilot and supervised by a human test analyst.

Start by reproducing the synchronization flow on iOS, Android, or Windows after deleting the extra .qgs/.qgz file from the server. Trace how the mobile app handles the existing multiple-project-files state during pull; done means synchronization succeeds, the warning clears, and the project becomes openable without requiring a fresh download.