feat(error): add error handling and rollback support

[CalvinAllen]

Summary

Adds error handling with rollback support to prevent leaving the solution in a broken state.

Changes

• Wrapped entire rename operation in try-catch
• Track state flags:
  • projectRemovedFromSolution - true after project is removed
  • projectReaddedToSolution - true after project is re-added
• On failure:
  • Mark current step as failed in progress dialog (shows red X)
  • If project was removed but not re-added, attempt to re-add it at its current location
  • Show error message box with details
• Removed TODO comment since all issues are now implemented

Rollback behavior

If an error occurs after the project is removed from the solution:

1. Try to find the project file (at new path or original path)
2. Re-add it to the solution in its original solution folder
3. This ensures the solution isn't left without the project

Test plan

• Rename a project successfully - should work as before
• Simulate failure (e.g., read-only file) - should show error and attempt rollback
• Verify failed step shows red X icon in progress dialog
• Verify error message box appears with details

Closes #13