Extension v1.0.1

First release submitted via the automated AMO + Chrome Web Store pipeline.

No user-facing changes vs v1.0.0 — this release validates the new
automation infrastructure (in-house OAuth helper, in-house CWS upload,
web-ext sign for AMO) end-to-end. Subsequent releases will go through
this same path.

Artifacts attached: chrome zip, firefox zip, safari zip, source bundle.