refactor(guestbook): move guestbook mode switch to invokable controller
refactor(guestbook): extract file download action to invokable controller
refactor(guestbook): extract reply action to invokable controller
refactor(guestbook): extract edit action to invokable controller
chore: change psalm config
feat: move delete post action to invokable controller
refactor(guestbook): move clear action to invokable controller
refactor: introduce controller context service
feat: support invokable controllers
refactor(guestbook): change data structure for template