fix(connections): safe mode level no longer resets when opening a table (#1351)

[datlechin]

Fixes #1351.

Problem

Changing the Safe Mode level from the toolbar didn't stick: opening a table (or any reconfigure of the connection) reset it back to the connection's saved default. ConnectionToolbarState.update(from:) hard-set safeModeLevel = connection.safeModeLevel every time, and MainContentCommandActions.safeModeLevel also read the saved default, so the live choice was lost.

Fix

The live level now lives on the session, not just the saved connection:

• ConnectionSession gains a safeModeLevel, seeded from connection.safeModeLevel on connect.
• ConnectionToolbarState.update(from:) no longer overwrites safeModeLevel; syncFromSession resolves it from the session (falling back to the connection default), so a reconfigure keeps the live value.
• The toolbar's Safe Mode badge writes through onSafeModeChange → MainContentCoordinator.setSafeModeLevel, which updates both the toolbar state and the session (DatabaseManager.setSafeModeLevel).
• MainContentCommandActions.safeModeLevel reads the live toolbar state instead of the saved connection.

Tests

ConnectionSessionTests (session seeds from the connection default) and ConnectionToolbarStateTests (the live level survives an update(from:) and tracks the session).