Join should report total_byte_size

### Is your feature request related to a problem or challenge?

Currently joins don't propagate `total_byte_size` even though they have estimates on the cardinality

### Describe the solution you'd like

Propagate this info based on the output projection.

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by locating the join cardinality-estimation logic and the code that propagates `total_byte_size` through output projections. Trace how join estimates are built, then verify that the reported byte size reflects the projected output and add or update focused tests for the resulting estimate.

Written by the indexing model from the issue text.