feat: /ctx セーブスロット + v1.1.1

refactor: v1.1.0 — Skill個別分割+triggers追加+reflect別ファイル運用+devil-checklist移動

fix: gitignore .devcontainer (local test only)

fix: remove personal email, update author URL to eris-ths

remove: devcontainer from repo (test-only)

chore: add devcontainer for clean environment testing

fix: marketplace.json source "." -> "./" (validation fix)

feat: add marketplace.json + fix install instructions

fix: correct plugin install syntax (@marketplace-name)

fix: correct plugin install commands to use /plugin marketplace add

chore: add .gitignore, add shell execution warning to ship.yml docs

chore: add MIT LICENSE file

fix: correct install instructions, translate getting-started to Japanese

docs: add installation guide, reverse-lookup usage guide, remove internal link

fix: update repository URL to independent eris-ths org