Multi-threaded engine, fix lost-stop timeouts, auto update check (v1.1.0)

[ccharafeddine]

Summary

Fixes analysis timing out after moving quickly. The stockfish.js worker queues go while a previous search is still unwinding, but runs stop immediately. That meant a stop could land before the search it was meant for and be lost. The 3s stop watchdog then rebuilt the engine (recompiling the 113MB WASM) and analysis failed. I reproduced it in Chromium: on the old code, 16 of 35 rapid positions got no analysis. Changes:

• stop is re-sent every 100ms until its bestmove arrives, and the stop watchdog is raised to 8s.
• A final result whose lines all fail the legality filter now shows a retry warning instead of spinning forever.
• New regression tests (src/engine/stockfish.test.ts) use a fake worker that mirrors the real command queueing. They fail without the fix.

Engine speed and strength

• The app was shipping the single-threaded Stockfish build (public/stockfish.* byte-matched stockfish-18-single), so the Threads option was ignored. It now uses the multi-threaded NNUE build: about 4× nodes/sec on 4 cores.
• The engine is served and copied from the stockfish npm package by a Vite plugin, replacing the committed 113MB LFS blob. .gitattributes and the LFS checkout in the workflows are removed.
• Startup now waits for readyok after Threads/Hash, and the redundant ucinewgame (a second clear of the 512MB hash) is gone. Warm start is about 3.5s to the first move.
• New think time setting (1/3/5/10s), and the analysis debounce is shorter.

Update check

• The app now checks for updates automatically at startup. This can be turned off in the settings menu.
• When a newer release exists, a banner appears (dismissible per version) and the settings gear shows a dot.

Electron / app

• Fixed port with a random fallback, so localStorage settings persist across launches and the WASM code cache works.
• Files are streamed with ETag/no-cache instead of a blocking readFileSync.
• Single-instance lock.
• Fonts are bundled via @fontsource. Google Fonts was blocked by the app's own CSP/COEP.
• Version bumped to 1.1.0.

Testing

• npm run lint, npm test (45 tests) and npm run build pass.
• Stress-tested in Chromium with rapid position changes: no engine restarts, and the first line arrives within about 1–100ms of each change.
• UI end-to-end run (drag moves, settings, mocked release banner) against the Electron server code.
• I haven't launched the Electron app itself.

🤖 Generated with Claude Code

https://claude.ai/code/session_017ZHKbLKcpoa8QJGzqkbDTJ

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