ComposerHistoryState reducer + Wire в FreeFormInput

## Что это `ComposerHistoryState` — pure reducer: actions PUSH / NAVIGATE_UP / NAVIGATE_DOWN / RESET. Wire в `FreeFormInput` через React selector hook. State per-session, persisted в SQLite. ## Зачем Reducer-pattern даёт testability, time-travel debug, простую интеграцию с middleware (audit emit на каждую submission). Single source of truth для history. ## Источники вдохновения - [emcie-co/parlant](https://github.com/emcie-co/parlant) — composer state - [vercel-labs/tersa](https://github.co ## 🔗 Linear - [PZD-135](https://linear.app/kuhjie/issue/PZD-135) (match confidence: 0.44)