fix(tool-server): cap concurrent simctl device listing

[iroiro147]

Summary

Fixes #327.

Adds a host-wide filesystem lock around local xcrun simctl list devices --json so multiple Argent tool-server processes do not spawn concurrent CoreSimulator discovery calls. Both listIosSimulators() and the simulator watcher now share readSimctlDevices().

The lock path also handles the two race cases found during review:

• fresh empty/partial lock files are treated as live using filesystem mtimeMs fallback
• stale lock cleanup is serialized through a sidecar .cleanup lock so competing stale cleaners cannot delete a fresh holder's lock

Tests

• npm test -w @argent/tool-server -- --run test/ios-devices-runtime-kind.test.ts test/list-devices-deadline.test.ts test/simulator-watcher-init-failure.test.ts test/list-devices.test.ts
• npm run build
• npm run build -w @argent/tool-server
• npm run typecheck:tests -w @argent/tool-server
• npm run lint -- --no-warn-ignored packages/tool-server/src/utils/ios-devices.ts packages/tool-server/src/utils/simctl-config.ts packages/tool-server/src/utils/simulator-watcher.ts packages/tool-server/src/tools/devices/list-devices.ts packages/tool-server/test/ios-devices-runtime-kind.test.ts packages/tool-server/test/list-devices-deadline.test.ts packages/tool-server/test/simulator-watcher-init-failure.test.ts
• npx prettier --check packages/tool-server/src/utils/ios-devices.ts packages/tool-server/src/utils/simctl-config.ts packages/tool-server/src/utils/simulator-watcher.ts packages/tool-server/src/tools/devices/list-devices.ts packages/tool-server/test/ios-devices-runtime-kind.test.ts packages/tool-server/test/list-devices-deadline.test.ts packages/tool-server/test/simulator-watcher-init-failure.test.ts
• git diff --check

Note: I did not use the full @argent/tool-server Vitest suite as a local gate because this environment blocks several unrelated socket/process-list tests with listen EPERM / host-tool permission errors. The focused tool-server slice above is clean.

[hubgan]

Thanks for taking the time to work on this. I appreciate the contribution. There are a few areas that need some additional refinement before this is ready to merge.

[iroiro147]

Thanks for the detailed review, Hubert. I pushed a follow-up commit that reworks the simctl-list lock handling around explicit ownership metadata.

What changed:

• the main lock and cleanup sidecar now carry an owner token, pid, and createdAt
• stale cleanup no longer removes a lock while the recorded owner process is still within the live-owner grace window
• very old locks/cleanup sidecars can still be recovered even if the recorded pid is alive again, which covers pid reuse after a crash
• release only unlinks when the current owner token still matches, so an old holder cannot delete a successor lock
• listIosSimulators() no longer hides lock acquisition/wait failures as an empty simulator list, while simctl/xcrun failures still preserve the existing empty-list fallback
• the aggregate list-devices tool catches that iOS branch failure so Android/Chromium/Vega results are still returned
• added coverage for live-owner stale locks, pid-reuse recovery, dead-owner stale locks, orphaned cleanup sidecars, lock acquisition failures, simctl failure fallback, and aggregate list-devices degradation

Re-ran:

• npm test -w @argent/tool-server -- --run test/ios-devices-runtime-kind.test.ts test/list-devices.test.ts test/list-devices-deadline.test.ts test/simulator-watcher-init-failure.test.ts
• npm run typecheck:tests -w @argent/tool-server
• npm run build -w @argent/tool-server
• npm run lint
• npx prettier --check packages/tool-server/src/utils/ios-devices.ts packages/tool-server/src/tools/devices/list-devices.ts packages/tool-server/test/ios-devices-runtime-kind.test.ts packages/tool-server/test/list-devices.test.ts
• git diff --check