External Signals traces for dependency switching and batch effects

[PerchAnton]

I made an external @preact/signals-core example for interaction-check, a JSONL regression runner I maintain. A computed value switches between two signals; the traces assert that inactive dependencies do not notify and a batch exposes only the final selection.

There is also an effect-disposal trace and a check that an invalid batch argument causes no partial writes. Would this be useful as an optional reproduction example? No Preact rendering or DOM behavior is claimed.

Adapter · Three traces · External PR. Tested with @preact/signals-core 1.14.4: 3 scenarios / 13 steps pass locally on macOS, Node 24.19.0.

From that checkout, with Python 3.10+ and Node 24.19.0:

npm --prefix adapters/javascript ci --ignore-scripts --no-audit --no-fund
python interaction_check.py scenarios/preact-signals/*.json -- node adapters/javascript/main.mjs preact-signals