feat: use x.com/AISuperDomain as entry point

fix: add trailing space after last hashtag to prevent autocomplete dropdown

refactor: rewrite workflow based on battle-tested best practices

feat(skill): harden x-post-browser with compose dialog, preflight checks, permalink

docs(skill): use execCommand+verify to preserve hashtags and avoid residue

fix(skill): use evaluate insertion to preserve X hashtags

docs: add README for x-post-browser skill

feat(skill): add x-post-browser