Make model comparison compact and accessible

[mattfaltyn]

Summary

• Move model comparison out of narrow odds cells into a bounded, keyboard-accessible dialog.
• Show each physical and market model as a compact result row; keep inputs, quote checks, and prospective/retrospective evidence in per-model disclosures.
• Make unavailable reasons readable while retaining exact reason codes in details.

Verification

• scripts/verify-fast: 401 backend and 151 frontend tests passed.
• Focused Chromium dialog tests passed at 1280 px, 390 px, and 320 px, including Escape and focus restoration.
• scripts/verify passed through build; local Playwright server start was blocked by the already-running development app on ports 8000/5173. PR CI runs the full command in a clean environment.