E2E: blog flow (index → article → lang switch)

[wab]

Parent

#121

What to build

Playwright golden path: blog index → click article → switch language on article → assert URL + content swap.

Acceptance criteria

• Reuses Playwright setup from Test: Playwright setup + homepage golden path E2E #134
• Visit /blog, click first article
• Switch language, assert URL prefix changes and content rerenders in target lang
• Test passes in CI

Blocked by

• Test: Playwright setup + homepage golden path E2E #134