cli: HN top-comment pull-quote under headline

[manu-rajput-dodge]

Deferred from the UI refresh (spec §14.4). Surface the highest-voted comment from an HN story directly in the slot.

What

For HN-sourced NEWS slots, pull the first 2 lines of the top-voted comment and render it under the headline as a muted pull-quote with a leading `›` glyph. Gives the dev signal they'd normally have to click through for.

Mockup

```
▍ news · live 2h ago
──────────────────────────────────────────────────────────────────
[HN] Hacker News · ↑ 418

Show HN: I built a Claude Code plugin
that auto-generates PR descriptions

› "Replaces three prompts I had memorised
— saves about 6m per PR." · top comment

──────────────────────────────────────────────────────────────────
[D] open · [B] save · [S] skip · [K] kill
```

Why deferred

Backend pipeline cost. The HN API requires a second fetch (per-story comment tree) and a ranking pass to pick the top comment. The meta-row in v1 doesn't have provision for the extra 2 lines.

Acceptance

• Backend fetches top comment lazily (only when story makes the surfacing queue)
• Pull-quote truncates to 2 lines with single trailing ellipsis
• Only renders when terminal width ≥ 80 cols (folds when narrow)
• HN-only — non-HN sources don't render this row

References

• Spec: `docs/superpowers/specs/2026-05-20-distro-tv-ui-refresh-design.md` §14.4
• Variant preview during brainstorm at `.superpowers/brainstorm/.../07-news-details.html` (card "quote")