Virtualize Log component with scrollback limits and infinite scroll

[devin-ai-integration]

Summary

Virtualizes the React Log component by configuring xterm.js with a bounded scrollback buffer (5000 lines) and adding infinite scroll behavior to fetch older logs from Redis when the user scrolls to the top.

Changes:

• Set scrollback: 5000 on xterm to cap DOM/memory usage regardless of stream length
• Added scroll-to-top detection via xterm's onScroll callback to trigger paginated fetches from Redis (askRange with FETCH_BATCH_SIZE = 200)
• Track earliest stream ID via ref for proper pagination
• Added proper socket cleanup on component unmount (disconnect(), off())
• Removed unused Line import and response state array
• Memoized callbacks with useCallback to prevent unnecessary re-renders

Review & Testing Checklist for Human

• Start all services (Redis, Go server, Node socket server, React dev server) and pipe a large stream (e.g., ./app/runner.sh | ./app/app) to verify the xterm scrollback limit caps at 5000 lines
• Verify scrolling to top triggers loading older log lines from Redis
• Confirm new live-streamed lines still appear at the bottom in real-time

Notes

• xterm.js already virtualizes DOM rendering (only renders visible rows). This change adds the scrollback limit and infinite scroll to make the overall system properly virtualized end-to-end.
• NODE_OPTIONS=--openssl-legacy-provider is required when building with Node 22 + react-scripts 4.x.

Link to Devin session: https://app.devin.ai/sessions/62e7884e8d894e378e8df86605f9c1bd
Requested by: @braeden

[devin-ai-integration]

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