perf: make alerts immediate and map interactions lighter

[svg8bit]

Summary

• render the lightweight activity rail outside the dynamically loaded MapLibre bundle and refresh stale feeds independently of map readiness
• enforce alert policy: only fresh 24h odds moves of at least 20 percentage points and current Large BUY trades of at least $200K; remove volume-only, 1h, snapshot, SELL, expired, and mismatched alerts
• remove the runtime night-earth raster and expensive glow passes, lower constrained WebGL backing resolution without shrinking the CSS map, and stop projecting 71 DOM hit targets on every render frame
• extend deterministic E2E coverage and benchmark activity-layer readiness

Performance (1917x779, 4x CPU, 3-run median)

• map ready: 9223ms -> 6145ms (-33.4%)
• drag: 2.9 -> 5.8 fps; main-thread task time -46.4%
• zoom: 2.7 -> 4.5 fps; main-thread task time -46.5%
• requests: 50 -> 28 (-44.0%); transfer: 914.6KB -> 733.0KB (-19.9%)
• full CSS canvas preserved at 1917x745; constrained backing store 1150x447
• activity layer ready in 325ms median and no longer waits for WebGL

Validation

• npm run check
• npm run test:e2e (33 passed)
• deterministic 1672x941 world and regional captures inspected at original resolution
• git diff --check

The optional historical-reference comparator cannot run because docs/reference/map-approval-1672x941.png is not present in the repository; the current deterministic visual E2E tests passed.

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Project	Deployment	Actions	Updated (UTC)
oddsfront	Ready	Preview	Aug 22, 2026 1:28pm

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