chore(repo): remove opencode references

feat(packs): add harness and codex review loop bundles

refactor: migrate script tooling to tools and streamline codex multi-agent docs

feat: add codex role templates and CLI utility docs

refactor: rename toolkits/ to packs/ and add harness entry

docs: redesign README banner and expand module documentation

docs: normalize top-level README structure

chore: add MIT license file

refactor: reorganize instruction, config, and prompt directories

feat: add codex provider history migration tool

feat: add codex profile templates

feat: add chat history cleanup tooling

docs: sync directory layout after skills cleanup

feat: add fresh-branch slash command

docs: update architecture section and directory layout