Tighten right-sidebar sections

[dmnyc]

Summary

• Wrap each right-sidebar block (Live contracts, Highest liquidity, Market states) in a rounded-xl bg-slate-950/45 p-4 card so the sections read as discrete units, matching the stat cards on the left.
• Add a thin border-b border-slate-800/60 under each section heading.
• Highest liquidity: drop the redundant 1. rank prefix; render the value as a slate pill (rounded-md bg-slate-800/70) with tabular-nums, whitespace-nowrap, and a muted "BTC" unit so the column never wraps; add an empty-state row mirroring "Live contracts".
• Market states: hide zero-count rows and the whole section when every state is zero, so the panel doesn't enumerate empty buckets.

Test plan

• On a category with no live contracts and a single dormant market, confirm Live contracts shows the empty message, Highest liquidity shows one row with a slate pill (no wrap), and Market states shows only the Dormant row.
• On a busy category, confirm all three cards render with consistent spacing and the dividers under each heading line up.
• Resize the viewport down to xl breakpoint and verify the value pill stays on a single line and the question text truncates / wraps cleanly.