feat(ui): Add form design system with uswds styling

[LinnJS]

Description

This PR completes the migration of the UI package to use USWDS
(U.S. Web Design System) classes as the primary styling
approach, establishes a comprehensive testing architecture,
and improves type safety throughout the codebase.

The changes include:

• Migration of all components from Tailwind utilities to USWDS
  BEM classes
• Implementation of comprehensive unit and E2E testing with
  colocated test architecture
• Removal of all any types and unsafe type assertions for
  improved type safety
• Resolution of component import errors and test failures

This work ensures the UI package is production-ready with
proper USWDS styling, comprehensive test coverage, and
improved maintainability.

Type of Change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand
  areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my
  feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in
  downstream modules
• I have checked my code and corrected any misspellings

Screenshots (if appropriate)

N/A - Component styling and test infrastructure changes

Additional Notes

Test Coverage

• 123 unit tests passing across 7 test suites

• Playwright E2E tests configured for Storybook stories

• Tests colocated in tests directories within component
  folders

  Type Safety Improvements

• Created FieldValue type union for validation system

• Replaced unsafe type assertions with proper type guards

• Zero TypeScript errors or ESLint warnings

  Components Updated

• Button, Card, Form, Accordion, Alert, Badge, Typography
  components now use USWDS classes

• All components maintain backward compatibility while using
  USWDS as primary styling