Enhanced the `solved` plugin with comprehensive improvements to solution
handling and UI components:
- Use the `PostQuotedContent` core component for rendering accepted
answers
- Added `@tracked` state management for solution acceptance UI
- Refactored `acceptPost` and `unacceptPost` functions with better error
handling
- Updated topic models to safely track accepted solutions
- Added MessageBus integration for secure message publishing
- Improved test coverage adding MessageBus verification and system tests
for accepting/unaccepting answers.
Sérgio Saquetim
Jarek Radosz