feat(frontend): add market list filter/sort controls, pool bar, and o…

[afurious]

closes #772
closes #774
closes #775
closes #785

…dds display

• MarketFilters: status tabs (All/Open/Locked/Resolved), debounced fighter search (300ms), sort dropdown (Newest/Ending Soon/Biggest Pool), all state synced to URL query params with page reset on filter change
• PoolProportionBar: three-segment bar (red/gray/blue for A/Draw/B), widths proportional to pool sizes with percentage labels, smooth CSS transition, equal-thirds fallback when all pools are empty
• OddsDisplay: parimutuel multiplier (e.g. 2.50x) and implied probability per outcome, favorite highlighted with amber ring + FAV label, shows — on zero pool
• api.ts: add search field to MarketFilters for fighter name filtering

Closes

Closes #

What this PR does

Testing

Screenshots (frontend changes only)

Checklist

• I have read docs/contributing.md
• My code follows the naming conventions in the guidelines
• I have added or updated tests for my changes
• All tests pass locally (cargo test / npm test)
• Lint passes (cargo clippy / npm run lint)
• No console.log or unwrap() left in production paths
• No secrets committed