Rich blockquote element (footer / cite / background / border tokens)

[jackgranatowski]

Problem

Blockquotes are styled only within .sf-prose (italic + inline-start border/padding). There's no standalone, tokenised blockquote treatment (container background/shadow/radius, footer/cite styling, <figure><blockquote>…<figcaption> support) for use outside prose.

Scope

• Element/tokens in the optional components layer: --sf-blockquote-* (bg, border, radius, padding, footer/cite size/colour).
• Support figure > blockquote + figcaption attribution.

Acceptance

• Standalone blockquote styling driven by tokens
• Footer/cite + figure/figcaption handled
• Documented