Add configurable limits for databases and collections in tree view

Problem

Currently, when expanding a parent node in the tree view, all databases and collections are displayed. This can cause significant performance and usability issues when working with databases containing thousands of collections.

Solution

Implement configurable limits for the number of databases and collections shown in the tree view when a parent node is expanded. This should:

• Allow users to set maximum limits for how many items are displayed
• Show a "Load more" or similar indicator when items exceed the limit
• Be configurable through extension settings
• Improve performance and usability for large-scale database scenarios

Acceptance Criteria

• Add configuration settings for database and collection limits
• Implement pagination or "show more" functionality in tree view
• Document the new settings in the extension configuration
• Add tests for the new limits functionality

Start by locating the tree view expansion entry points and the extension settings configuration. Trace how databases and collections are loaded, then determine where limits and a Load more indicator belong. Done means configurable database and collection limits work, excess items can be revealed, settings are documented, and tests cover the behavior.