132 standardize button components and styling

[krgjert]

Purpose

Make button styling consistent across the application and reduce duplicated styles by using shared components.

Changes

• Added default, dark, secondary, danger, and text variants to Button.
• Added support for navigation through <Button to="...">.
• Created TextButton using the shared button component.
• Migrated account, authentication, build, notification, and catalogue actions to shared buttons.
• Removed local colour and hover overrides from migrated buttons.
• Moved build-action labels and optional icons into AddToBuildButton.
• Standardised header action styling and removed borders from component-list action icons.
• Updated the Clear build dialog to use secondary and danger.

Related issues

None

Checklist

• I have reviewed my own changes.
• The changes meet the linked issue's acceptance criteria, where applicable.
• I have verified the changes and recorded the results above.
• I have added or updated tests where needed.
• I have updated documentation where needed.
• I have included screenshots for visual changes, or marked them not applicable.

[wilhelsr]

Approved, this is a way better than before.