Enhance v1 recipe error handling and progress feedback

[danyeaw]

Checklist

• I added a descriptive title
• I searched open requests and couldn't find a duplicate

What is the idea?

Clear error messages and progress feedback for v1 recipe builds.

Why is this needed?

Users need to understand failures and see progress.

What should happen?

1. Catch rattler-build exceptions and re-raise as CondaError with context
2. Add context-specific error messages
3. Show progress (variant X/Y, package name/version)
4. Add tests for error cases

Additional Context

• At minimum: re-raise all exceptions as CondaErrors
• Use progress_callback and BuildResult.log

[jsmolic]

I'm working on this issue. The in-progress PR using py-rattler-build for v1 recipes (#5924) already implemented parts of this issue, such as progress reporting and raising some of the rattler-build exceptions.