Improve UI components with tooltips, accessibility fixes, and reusable locale/theme selectors

[tjementum]

Summary & Motivation

Add tooltip support to all form field components to provide better user guidance. Form fields like account name, region, and title now have contextual tooltips explaining their purpose.

• Add MultiSelect component for multiple selection dropdowns.
• Extract LocaleSwitcher and ThemeModeSelector into reusable components.
• Add fixed dialog width utilities (w-dialog-md, w-dialog-lg) using @Utility directive to prevent layout inconsistencies across languages.
• Add button variant to Link component for consistent styling.
• Fix Modal component to pass props only to ModalOverlay, preventing prop spreading issues.
• Lock verification code input after pasting to prevent extra characters.
• Remove incorrect aria-hidden attributes from Table wrapper divs.
• Add aria-label to newsletter email input for accessibility.
• Remove Dutch (nl-NL) language support from the application.

Downstream projects

1. Remove Dutch language translations by deleting application/your-self-contained-system/WebApp/shared/translations/locale/nl-NL.po.

2. Update all Dialog components to use the new standard width utilities instead of max-w classes. Replace sm:max-w-lg with sm:w-dialog-md and similar patterns with sm:w-dialog-lg for larger dialogs.

- <Dialog className="sm:max-w-lg">
+ <Dialog className="sm:w-dialog-md">

Checklist

• I have added tests, or done manual regression tests
• I have updated the documentation, if necessary

[linear]

PP-622 Improve UI components with tooltips, accessibility fixes, and reusable locale/theme selectors

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
1.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud