Add support for listing and setting Azure DevOps work item states from the
integration layer. New helpers build and validate JSON-patch payloads and
expose two Tauri commands so the frontend can enumerate available states
and apply state changes. The Issue Center now loads Azure states and can
change an issue's state; dialog dismiss controls and related CSS were
consolidated and board UI feedback was simplified for clarity.
- Add Tauri commands to list and set Azure work item states.
- Load and present Azure states in Issue Center and allow state changes.
- Unify dialog dismiss attributes and refine hover/focus styling.