Add creation flow for integration issues and Azure work items.
Expose Tauri commands to list Azure projects and types.
Also add a command to create integration issues and return the created item.
Preserve the target repository when provider responses omit it and return
the created issue information to the UI.
- Implement Azure-specific URL and payload handling and creation logic
- Add a Svelte CreateIssueDialog and integrate it into IssueCenter
- Add tests to validate creation requests and created-issue parsing