Two CI failures landed together on master after PR #194 merged:
1. **components-metadata.json stale.** The `power-supply` thumbnail
in scripts/component-overrides.json was updated (grey placeholder
→ branded PSU SVG with voltage/current labels) but the generated
JSON wasn't regenerated. The pre-merge check
`git diff --quiet frontend/public/components-metadata.json` now
fails on master. Fix: `cd frontend && npm run generate:metadata`,
commit the result.
2. **Frontend Tests > test (20/22): vitest worker hang.**
`circuit-simulation-service.test.ts` had been calling
`service.start()` in ~10 tests without storing the returned
unsubscribe handle. Each call subscribes the service to the
simStore; the listener captures the service + scheduler in
its closure. After all tests complete, vitest's forks pool
tries to terminate the worker but the still-active listeners
keep the event loop pinned, producing:
"Worker exited unexpectedly / Timeout terminating forks worker"
All assertions actually pass — only the worker shutdown hangs.
Fix: introduce a `startTracked(service)` helper that records
the unsubscribe in a module-level array, plus an `afterEach`
that drains the array. `__resetMixedModeScheduler()` still runs
after to dispose the scheduler singleton. Replaced all 9 raw
`service.start()` callsites.
Both are independent of any production code change. The fix is
test/scaffolding only.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>