Branding tasks

• [x] Add horizontal and stacked logos with the title, and icon-only artwork without the title, in both themes.
• [x] Replace placeholder branding and update favicons.
• [x] Add the supplied Recreation.gov logo and Meet Justin portrait.
• [x] Show logo variations in the design system preview.
• [x] Add component coverage for assets, title removal, theme changes, and proportions; refresh DOM snapshots.
• [x] Check five routes at 375px and 1440px in both themes and verify live theme switching.
• [x] Review and refresh browser baselines and run the visual regression check.
• [x] Complete repository checks and prepare the change for review.