Fix connection permission loss when updating server configurations

[Copilot]

Problem

When changing any connection property (password, host, port, etc.) from the main connections panel as a global admin, teams and users that previously had access to the connection lose that access. This forces administrators to manually re-assign connections to teams/users after every configuration change.

Root Cause

The issue occurs because AdminModel uses ServerConfig.equals() to determine if a cached ServerModel can be reused. Since ServerConfig.equals() compares ALL properties (name, username, password, host, port, database, etc.), any property change causes the equality check to fail. This results in:

1. AdminModel creating a new ServerModel instance
2. The old ServerModel (with team/user permissions) being discarded
3. Permission associations being lost

Solution

This PR fixes the issue by modifying how AdminModel identifies servers for caching purposes:

ServerModel Changes

• Changed serverConfig field from final to allow updates
• Added updateServerConfig() method to update configuration while preserving the instance
• Added validation to prevent server name changes via this method
• Clear dependent cached objects when configuration is updated

AdminModel Changes

• Modified refresh() methods to use server name comparison instead of full object equality
• When a cached ServerModel exists with the same name, reuse it and update its configuration
• This preserves ServerModel instances and their associated permissions

Impact

Before Fix:

// Full object equality - fails when password changes
if(cacheSM.getServerConfig().equals(sconf)) {
    sm = cacheSM;  // Never executed when any property changes
} else {
    sm = new ServerModel(connectionManager, sconf);  // Always creates new instance
}

After Fix:

// Name-only comparison - succeeds when server name matches
if(cacheSM.getServerConfig().getName().equals(sconf.getName())) {
    sm = cacheSM;  // Reuses existing instance
    sm.updateServerConfig(sconf);  // Updates config while preserving permissions
}

Testing

• Created comprehensive tests validating the fix preserves object identity
• Verified that permission systems maintain references to the same ServerModel
• Confirmed that connection functionality works correctly with updated configurations
• No regression in existing functionality

Benefits

• ✅ Team/user permissions are preserved during connection updates
• ✅ Administrators no longer need to re-assign connections after configuration changes
• ✅ Improved user experience and reduced administrative overhead
• ✅ Better performance through reduced object creation

This is a surgical fix that resolves the permission issue while maintaining full backward compatibility.

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