Add GUI restore functionality for Server Backups (restore point selection)

[Adrien-MUHLHEIM]

Description

Currently, there is an option to back up the Borg server database through the GUI. However, there is no corresponding way to restore these backups from the interface.

Restoration can only be performed manually (e.g., via CLI), which makes the process less accessible and more error-prone.

This feature request proposes adding a dedicated GUI section (e.g., a new tab or panel) that allows users to:

• View available server backup snapshots
• Select a restore point
• Trigger a restore operation directly from the web interface

Use Case

A typical scenario:

• An administrator performs regular server backups using the built-in backup feature.
• After a configuration error, data corruption, or accidental deletion, the server needs to be restored to a previous state.
• Currently, the administrator must:
  - Access the system via CLI
  - Manually locate backup files
  - Execute restore commands

This process can be:

• Time-consuming
• Error-prone
• Difficult for less experienced users

With a GUI-based restore feature:

• The administrator could simply:
  - Navigate to a "Server Backups" tab
  - Select a restore point from a list
  - Click Restore

This would:

• Improve usability
• Reduce risk of mistakes
• Make disaster recovery faster and more reliable

Alternatives Considered

No response

[marcpope]

I'll look at adding this, should be fairly simple.

[marcpope]

I've spent a lot of time researching this and there's potentially 3 restore scenarios:

1. Rollback on a running server. "I just made a config change and broke something — undo." Local backup file already on disk. The easiest to engineer.

2. Disaster recovery on a fresh server with S3 backups. Old server is dead. Fresh bbs-install on new hardware. DB is empty so there are no S3 credentials stored. User has to enter the S3 endpoint/bucket/keys before it can do anything useful.

3. Disaster recovery on a fresh server with backup file in hand. Old server is dead. User has the .tar.gz file (downloaded from S3 manually, or copied off the dead machine's mounted disk). Just needs to upload/SCP and restore.

Then there's also some potential issues:

1. The fresh BBS server doesn't have the same paths configured. We'd have to re-write the paths, huge and complex feature. Or, check if the paths exist before restore, still complex.
2. Checking permissions to make sure everything works as expected, also another complex endevor.

The current bbs-restore cli tool actually has these issues too and was written well before we had a lot of these new storage offerings so the tool was more simple. If the paths aren't the same, you might run into a lot of issues. I would call the backup feature not great and could use some serious re-engineering time.

For now, I am going to put this into the v3 feature pile.