fix(ui): White screen when hedgehog mode loses its WebGL context

[charlesvien]

Problem

Hedgehog mode mounts a full-window game canvas at z-index 999998. When its WebGL context dies (GPU reset, context eviction after sleep or occlusion), Chromium composites the dead canvas as an opaque white sheet covering the entire app. The app keeps running underneath (the overlay is pointer-events: none) and nothing ever recovers it: the white screen of death.

Changes

On context loss the game is destroyed and removed from the DOM immediately, reported via captureException, then remounted after 2s (max 3 attempts, after which the overlay stays hidden until the setting is toggled). Detection goes through the HedgehogModeHost seam: the adapter fires an onContextLost callback and exposes isContextLost() on the handle, which a 10s poll (skipped while hidden) and a re-check on window refocus consult, so a swallowed loss event still tears the canvas down.

How did you test this?

• 8 unit tests: teardown and reporting on loss, poll and refocus detection, bounded remount, toggle cycle, unmount.
• Typecheck and Biome pass for @posthog/ui and apps/code.
• Live: with hedgehog mode on, run WEBGL_lose_context.loseContext() on the game canvas in devtools; hedgehogs respawn instead of white-screening.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit b60227d.}

[greptile-apps]

_{Reviews (1): Last reviewed commit: "remount hedgehog mode on WebGL context l..." | Re-trigger Greptile}

[github-actions]

Solid bug fix with well-structured effects, proper cleanup of all listeners/timers/subscriptions, a defensive fallback polling mechanism, and comprehensive tests covering toggle cycles, repeated context losses, and unmount. The bot comment was on an older commit and is resolved; the new code's effect dependency on gameDead eliminates the re-registration gap the comment identified.