Added notification when a project has a newer version available on the server

[gabriel-bolbotina]

Added a function in mergin api that checks if the project needs a sync and fires a notification in case it is needed.

Tested to work for the currently open project and when switching from one project to another

Use case below:
https://github.com/user-attachments/assets/e0c01bec-5a55-4e22-82a4-2a50c673825b

[github-actions]

Pull Request Test Coverage Report for Build 23610078756

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 116 unchanged lines in 5 files lost coverage.
• Overall coverage increased (+0.09%) to 59.875%

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Files with Coverage Reduction	New Missed Lines	%
mm/app/attributes/attributecontroller.cpp	1	76.83%
mm/app/notificationmodel.h	3	50.0%
mm/core/merginapi.cpp	15	75.34%
mm/app/notificationmodel.cpp	18	49.47%
mm/app/activeproject.cpp	79	70.37%

Totals
Change from base Build 22999470615:	0.09%
Covered Lines:	8804
Relevant Lines:	14704

---

💛 - Coveralls

[github-actions]

📦 Build Artifacts Ready

OS	Status	Build	Info	Workflow run
macOS Build	📬	Mergin Maps 65151 dmg	Expires: 10/06/2026	#6515
linux Build	📬	Mergin Maps 65261 x86_64	Expires: 10/06/2026	#6526
win64 Build	📬	Mergin Maps 57101 win64	Expires: 10/06/2026	#5710
Android Build	📬	Mergin Maps 782511 APK [armeabi-v7a]	Expires: 10/06/2026	#7825
Android Build	📬	Mergin Maps 782551 APK [arm64-v8a]	Expires: 10/06/2026	#7825
iOS Build	📬		Build number: 26.03.876611	#8766

[Withalion]

It will need some more work as mentioned in main.qml. Also I don't really like the visuals of the notification. Why is the text a link? I propose to use the same design as we want to do in filtering notifications (Figma). It would be great to replace the close icon with "sync" button, let's discuss it.

[github-actions]

📦 Build Artifacts Ready

OS	Status	Build	Info	Workflow run
macOS Build	📬	Mergin Maps 65781 dmg	Expires: 24/06/2026	#6578
linux Build	📬	Mergin Maps 65891 x86_64	Expires: 24/06/2026	#6589
win64 Build	📬	Mergin Maps 57731 win64	Expires: 24/06/2026	#5773
Android Build	📬	Mergin Maps 789051 APK [arm64-v8a]	Expires: 24/06/2026	#7890
Android Build	📬	Mergin Maps 789011 APK [armeabi-v7a]	Expires: 24/06/2026	#7890
iOS Build	📬		Build number: 26.03.882911	#8829

[Withalion]

Besides the comments below, the project list shows information that user has "pending changes to synchronise" even though there are no changes done to the project locally, if there is newer version of project available on server. I don't think we want to show that info if there are no local changes.

[Withalion]

Instead of passing MerginApi emit signal after project is reloaded and connect it to MerginApi::isProjectSyncNeeded()

[Withalion]

Suggested change