chore(release): exclude scoped chore/test/docs commits from the changelog

The changelog filters used bare prefixes ("^chore:"), which do not match
the scoped conventional-commit spellings this repo actually writes
("chore(ci):", "test(membership):"). Internal commits therefore leaked
into user-facing release notes — v0.16.0 shipped with

    ### Other
    * 6d39fe5...: chore(ci): bump golangci-lint to v2.13.1 (@gammons)

which is not something a user has any use for.

Make the scope optional with (\(.*\))? so both spellings are excluded,
and add style/ci while here.

Verified against real subjects from this repo's history: all five
chore/test/docs commits since v0.16.0 are now excluded, and the three
user-facing fixes still group under "Bug fixes".