fix(audit): resolve accessibility and lint issues batch 2/3
Fix accessibility violations, lint errors, and code quality issues across components and utilities:
- src/components (header, marketing, portfolio, ui): Remove unused props, fix a11y attributes, improve type safety
- src/content (cv/portfolio, marketing-content): Simplify markup structure, remove redundant components
- src/lib/axiom (client, server): Improve error handling and type definitions
- src/app/portfolio/page.tsx: Update imports for component changes
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>