[FR] Display Syncing Progress

### Description

I currently run Appflowy on a few of my devices and what I have noticed is that there are no visual indicators that let me know whether or not an instance of Appflowy is syncing or not. And inclusion of this type of indicator would let me know if one of my devices is up to date.

An example of this can be found in Joplin. The following is the video of Joplin's Sync Button

https://github.com/user-attachments/assets/216a3a7a-5935-4d4f-8611-a08cd3d2e6ac

I would like to have the following to be added to Appflowy:
- A syncing indicator on both desktop and mobile for when an Appflowy instance is syncing with a server
- A indicator for when an Appflowy instance has completed syncing
- A timestamp of the last completed sync or duration of time since last completed sync or both

### Impact

Better User Experience

### Additional Context

_No response_