chore(electron): remove a stray verification script committed by mistake

`electron/__dockverify.js` was a throwaway script I used to check the dock-icon
bitmap painting against a real Electron build while preparing #27. It was never
meant to ship — it is not referenced by any script, config, or test, it is not
wired into any npm task, and it only ever existed to print pixel values once.

It rode into #27 on a `git add -A` and has been sitting in the tree since. It
shows up as two informational `node:` protocol notices in `npm run lint`, which
is how a contributor found it (#46).

Sorry for the noise.