feat(ui): create the first branded Blade component set

[ibourgeois]

Goal

Create the first reusable component library so new screens are built from shared primitives instead of custom page markup.

Scope

• App shell primitives
• Toolbar item and navigation item components
• Page header
• Form controls such as button, input, textarea, and select
• Display primitives such as badge, avatar, panel, dropdown, and modal

Out of Scope

• Business-specific screens beyond proving component usage
• A large marketing-style design system site

Acceptance Criteria

• New foundation screens can be composed from shared Blade components
• Components support light and dark mode
• The component set matches the clean visual direction for the product

Dependencies

• Depends on feat(shell): create application shell and navigation architecture #4 and feat(theme): establish design tokens, light/dark mode, and user theme override hooks #5

Test Plan

• Add render coverage for critical components
• Manually verify components in representative screens