* refactor(docs): dedup identical Card/LinkCard styles

The .card and .sl-link-card rules (base, :hover, and .title) carried
byte-identical declaration blocks, which the whole-codebase jscpd check on
main flags as clones. Group the selectors so the shared surface treatment is
written once. Pure selector grouping — rendered output is unchanged.

Part of #5908

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* chore: Apply megalinter fixes

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Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: devantler <26203420+devantler@users.noreply.github.com>