#8078 improvement(ui): share missing resource states

Summary

• Add ResourceEmptyState for missing resources and replace seven product screens with the shared icon/title/description layout.
• Retain the 32px icon, 20px heading and spacing. Center wrapped text and normalize neutral text contrast and remove the obsolete ResourceNotFound wrapper.

Type of Change

• Refactor / maintainability improvement

Testing

• Full workspace type checks, lint, repository audits (including import and API validation), generators and docs checks pass.
• Complete EMCN test suite and relevant existing consumer suites pass.
• Before/after browser fixtures cover light/dark styling, narrow layouts and the affected interaction patterns. Fixtures are isolated controls, not full authenticated product flows.
• No landing-page changes or audit tooling included.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)