Prevent diff-heavy task renderer crash loops

[k11kirky]

Problem

Opening a diff-heavy task in the experimental chat thread could crash the Electron renderer. That renderer omitted the worker-pool limit used by the production conversation view, allowing the syntax highlighter to create its much larger default worker pool; recovery then reloaded the same task route and repeated the crash.

Changes

• Share one bounded diff-worker configuration across both conversation renderers.
• On a repeated renderer crash, clear the task route instead of reopening the same crashing view.
• Add regression coverage for the worker limit and recovery sequence.

How did you test this?

• pnpm exec biome check packages/ui/src/features/sessions/conversationDiffPoolOptions.ts packages/ui/src/features/sessions/conversationDiffPoolOptions.test.ts packages/ui/src/features/sessions/components/ConversationView.tsx packages/ui/src/features/sessions/components/chat-thread/ChatThread.tsx
• pnpm --filter @posthog/ui typecheck
• pnpm --filter @posthog/ui exec vitest run src/features/sessions/conversationDiffPoolOptions.test.ts src/features/sessions/components/new-thread/buildThreadGroups.test.ts src/features/sessions/components/incrementalConversationItems.test.ts
• pnpm --filter @posthog/code typecheck
• pnpm --filter @posthog/code exec vitest run src/main/utils/renderer-crash-recovery.test.ts src/main/utils/crash-diagnostics.test.ts

Automatic notifications

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

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Created with PostHog Code

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[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit f547221.}