Spectator UX/UI parity + load/perf harness

[xa8zz]

Summary

• Brought spectator UX/UI closer to the 2026-02-05 visual + V1 gameplay specs (parchment leaderboard, tabbed agent card, mobile drawer/sheet, map declutter + terrain richness, zoom tween + pan inertia).
• Added repeatable QA + performance tooling (parity screenshots, a11y + SR smokes, world-state perf harness, synthetic load mode + headless render perf runner).
• Added tracking docs under docs/plans/ as source-of-truth and progress logs.

How to Review

• Run local server + demo: npm run dev then npm run dev:demo:reset && npm run dev:seed && npm run dev:demo -- --party
• Open: http://localhost:3000/

Test Plan

• npm test
• npm run lint
• npm run typecheck
• npm run build
• npm run dev:a11y
• npm run dev:sr
• npm run dev:perf:world-state
• npm run dev:perf:map-render