Theme: broadsheet

Part of the #112 catalog (clinical lane). Depends on the lane infrastructure: #114 (clinical: CSS-only via template inheritance) / #118 (cutting edge: islands + token bridge).

## Brief

Print journalism: display serif masthead (proposed: Playfair Display, OFL) over a text serif, drop caps on posts, dateline metadata row, CSS-columns blog index at wide viewports. Light-first with a true-black night edition.

## Definition of done (every theme)

- [ ] `theme.exs` manifest: every token documented, colours as `light-dark()` pairs; `cherry config tokens.NAME` overrides work
- [ ] Gates green: no colour literals outside token definitions, token/CSS parity, deterministic build, `mix precommit` in the container
- [ ] Fonts subsetted latin woff2, self-hosted in theme assets, licence recorded in the CSS header (Noto precedent)
- [ ] Test coverage: theme added to the token-gate loop + a fixture build (folio) under this theme
- [ ] Print-clean `/cv/`; `prefers-reduced-motion` freezes any motion to first frame; content complete with JS off; zero third-party requests
- [ ] Agent visual QA per #113 before merge: harness screenshots (desktop/mobile × light/dark + print CV), findings fixed in one batch, one confirm round, screenshots attached to the PR
- [ ] Exhibition build + hub card (#116), gallery card (#117), CHANGELOG entry, themes list in docs

Start with catalog #112 and dependencies #114/#118, then locate the theme.exs manifest and theme assets. Run the token-gate loop and mix precommit in the container before checking a folio fixture build. Done means the listed gates, font and licence requirements, print/JS-off/reduced-motion checks, #113 visual QA, exhibition build, hub and gallery cards, CHANGELOG entry, and docs update are complete.

Written by the indexing model from the issue text.