test: add Playwright visual tests for cover card placement (#405)
* test: add Playwright visual tests for cover card placement (#358) Add cover image visual verification tests to visual.spec.mjs: - Desktop: verifies .article-cover renders above weekly content - Mobile (375px): verifies responsive cover card rendering The cover/frontmatter support (generate_content.py, article-cover.html, cover-card.html, fallback-card.html, opengraph.html, manage_image_registry.py, validate_content_images.py) is already complete on main. This PR adds the Playwright visual verification pass for cover placements as required by the acceptance criteria. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * fix: address review comments on visual cover tests - Assert cover bounding box is spatially above article content - Restrict mobile cover test to mobile projects only (skip in desktop/wide) - Remove redundant setViewportSize (projects already define viewport) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>