rebuild search dialog CMC-style (recent + featured + trending)

[Flotapponnier]

Summary

Full rebuild of the search dialog modelled on CoinMarketCap's pattern (the user's reference) with Linear's chrome polish (the canonical command-palette ref).

What's new

Idle state (no query) surfaces three sections:

• Recent chips — horizontal scroll with edge fade, X to remove individually, "Clear" link in the header. Persisted to localStorage (`ocb:search:recent:v1`, cap 7, dedup on id, same-tab sync via custom event).
• Live leaders cards — horizontal snap-scroll, 6 hand-curated benches. Each card shows the bench title + current drop journal framing #1 provider (with logo) + p50 value in mono accent. Data fetched once from `/api/citable` (already edge-cached 300s) on dialog mount.
• Trending list — vertical, 6 more curated benches with the same logo + leader + value treatment.

Query state — grouped by kind (Benchmarks / Products / Compare / Alternatives / Answers / Chains / Pages). Every row gets:

• Leader logo for benches, entity logo for products/chains, kind icon (Lucide) for the rest.
• Title + tiny kind label + description.
• ArrowRight that lights up on the selected row.

Polish

• Linear-style chrome: hairline border (`border-rule-strong/50`), single shadow, no accent focus ring, snappy 150ms open animation (handcrafted CSS keyframes: fade + 4px slide-down; tailwindcss-animate isn't installed).
• Mobile: full-bleed sheet, kbd footer hidden, X close button instead of esc kbd.
• Accessibility: dialog/aria-modal/aria-label, focus trap from cmdk, reduced-motion fallback in CSS, kbd hints rendered as real `` tiles.

Files

• `src/components/search/use-recent-searches.ts` (new) — localStorage hook with useSyncExternalStore + custom-event same-tab sync.
• `src/components/search/search-dialog.tsx` — full rewrite.
• `src/app/globals.css` — four CSS keyframes for the open/close transitions.

Test plan

• Open dialog (Cmd+K) → see Recent (if any) + Live leaders + Trending.
• Click a result → dialog animates out, route changes, item appears in Recent next time.
• Type "rpc" → results group by kind; selected row shows ArrowRight.
• X on a recent chip removes it; "Clear" wipes all.
• Mobile (375px): full-bleed sheet, no footer, X to close.
• Reduced motion: open is instant, no fade/slide.