refactor(widget): simplify state and hooks to support scalable interpretation flow

[digitalrisedorset]

• reorganise widget state to reduce coupling between UI and intent logic
• simplify hook structure and remove unnecessary dependencies
• clarify interpretation flow from user input → readiness → execution
• centralise state transitions (INTERPRETATION_READY, SUGGEST_CLICKED, etc.)
• improve handling of loading and async transitions
• prepare widget to support both text-driven and payload-driven scenarios

this refactor reduces complexity in the component tree and establishes a
clear orchestration layer, enabling the widget to scale without introducing
state inconsistencies or duplicated logic