Move inset buttons out of input fields (url/unit field)

[fabianhueske]

Package: @meteor/component-library

Some inputs (e.g. mt-url-field, mt-unit-field) render buttons inset inside the input field area. These should be rethought and moved outside the input, improving the layout of input field content.

Proposed improvement

• Move inset action buttons out of the input area (e.g. into an adjacent/attached control) for affected fields (mt-url-field, mt-unit-field, …)
• Rework input content layout so text/value no longer competes with inset controls
• Establish a consistent pattern for input-adjacent actions/addons across input components
• Preserve accessibility and keyboard/tab order for the moved controls
• Verify states (focus, disabled, error) and document in Storybook