Details rendering registrations and the details data generator lived on
`Grid` directly, separate from `DetailsManager`, which already handled
the rest of row details (visibility, data generation). This split state
across two places for one feature.

Move `setItemDetailsRenderer`'s renderer setup/cleanup logic into
`DetailsManager.setRenderer`, along with the data generator and
registration fields it used. `Grid.setItemDetailsRenderer` now just
delegates to `DetailsManager`.

🤖 Generated with Claude Code