* feat(stage-*): store chat session to indexdb
* refactor: remove prompt hash
* fix(stage-ui): enhance type guard for chat sessions export validation
* refactor(stage-ui): simplify chat session export and import logic
* refactor(stage-ui): update chat session management to use new data structure and improve export/import functionality
* refactor(stage-ui): enhance chat session persistence and management methods
* refactor(stage-ui): set and get idb value raw
* fix: type