fix: better prompt for slack paste

ci: avoid duplicate runs on PR branches

ci: trigger on push to all branches

fix: trim trailing whitespace when comparing editor content

feat: fall back to vim when $EDITOR/$VISUAL unset

docs: add edit command to README and CLAUDE.md

feat: add Editor trait, EnvEditor, edit command handler, and wire into CLI

feat: promote tempfile to regular dep for edit command

chore: fix ci again

chore: steer docs again

chore: avoid ci runs on doc changes

chore: doc update

chore: fix ci

feat: split in commands, add show

feat: wire main, docs