feat: replace V4 announcement banner with permanent header button - #3089

0 findings

No security vulnerabilities identified. This PR is a purely cosmetic UI refactoring: it exports a hardcoded constant URL (https://pro.aave.com/), adds a static navigation button to the application header, and removes redundant campaign banner configurations. All URLs are hardcoded strings with no user-controlled input, and no security-sensitive operations (authentication, authorisation, data handling, redirects based on user input) are affected.