- Add explicit agent/model mode toggles to QuickChatFAB and NewChatDialog
- Update session target logic so model mode starts chats with the KB agent while agent mode uses selected agents
- Clear opposite selections when switching modes and adjust placeholders/disabled states to match active mode
- Expand ChatView and QuickChatFAB tests to cover toggle visibility, mode switching, and session payload behavior
- Add useQuickChat coverage to verify agent-only switchSession calls omit model parameters
- Add KB agent fallback support in useQuickChat and allow switching sessions by agent plus model override
- Introduce session target key matching so same target reloads messages while different model selections create distinct sessions
- Update QuickChatFAB to lazy-load models, show model override UI, and keep quick chat usable for model-only conversations
- Add and expand hook/component tests to cover model selection flows, KB session creation, and default-model reset behavior
