[AXE] Navigation landmarks have no accessible names #147

Where: every page (Axe landmark-unique, 21 of 22 pages).

What's wrong: each page has several <nav> elements with no name, so screen-reader users hear "navigation, navigation, navigation" and can't tell them apart:

• main navbar: components/page-builder/components/navigation/navbar/StrapiNavbar.tsx (<nav data-navbar …>)
• footer: components/page-builder/single-types/footer/StrapiFooterMain.tsx (<nav>)
• blog category navigation: components/blog/BlogNavbar.tsx (<nav>, blog pages)

Done when:

• every <nav> has a unique aria-label from translations (apps/ui/locales/en.json), e.g. "Main", "Footer", "Blog categories"
• Axe reports no landmark-unique on any page
• follow-up for QA: the Playwright page objects can then switch from nav[data-navbar] to getByRole("navigation", { name: "Main" })